- (typically) eight lenses - four primes + fisheye, and three zooms
- sometimes another body
- on some club gigs, knee paddings
- sometimes 1-2 CompactDrive PD70x memory banks
- microfibre cloth and cleaning liquid
- accus

Going from main compartiment to the front:
20/1.8 or 20-35L; 28/1.8; 50/1.4; 100/2.0; 80-200L; 550EX; 580EX.
Lensbaby ;D;
iPod and Belkin media reader (I don't recommend this, except for emergency use);
tripod ring for 80-200;
Cable release;
Extention tube;
CP filter & step up ring;
Foot for the 550EX;
Batteries for flash and camera.
On top of it all: monopod.

my bag is similar to this one (K&H), very small but wich can carry so many things. before I tried the most famous bag brands (Lowerpro, Tamrac...), this one is not the best quality but the most convenient.

in, I have my D70 with his Sigma 30mm f1.4 fixed on, another Sigma 28/70 f2.8, and a 70/300 f4.5/5.6.
also batteries, memory cards, small brush for dust, ear plug, Maglite Solitaire fixed to my pass, pen, paper, visiting card, USB transfer cable.

At clubs my bag is a hard shoulder case that has room for 17-55 f/2.8 attached to D200, 70-200 f/2.8 VR and 85 f/1.8.
At the bottom there are extra battery and micro fiber cloth.

Other bags are LowePro Orion Trekker II and DryZone 200. Latter is capable to take also 10-20 Sigma, flash gun, and tripod on top, 12" PowerBook, card reader and LaCie 120 Gb mobile drive and two battery chargers. And few filters (ND, gradient and polarizers).
Sometimes the old Cosina is packed too with 50 f/1.8 and 135 f/2.8 Cosinon lenses with couple of rolls T-Max 400.

Lowepro nova5AW
2xBodies
17-40-f4.0, 70-200-f2.8
580ex, 2x converter,30g ipod+cables,extended cable release,monopod
Lots of Disposable ear plugs, plastic poncho(Raincoat),Cleaning kit,Mini led flashlight

I use Lowepro too, simply the best ;)
must have:
of course my Canon 5D
3 akkus and recharger
Compact Flash cards (4 Gigs, 2 Gigs + 1 Gig)
Lenses:
- Canon EF 24-70 mm 2.8
- Canon EF 50 mm 1,4
- Canon EF 15mm 1:2,8 Fisheye

if I go on a festival or a gig with very high stages I also pack my zoom lens:
- Sigma EX 70-200mm 2,8
I'm currently saving money for the Canon version of it with the image stabilizer...
also for festivals: my self made "rain protection" for my camera and lens

other:
Canon Speedlite 580EX Flashlight
Card reader
ear plugs (important!!!)
cleaning kit

By the way, one interesting thing are the open air festivals. I was on one two day festival where there was continuously music on three stages and there was no three song limit. Very exhausting, so I'd be interested on how to make things more bearable in that environment. Some thoughts:
- Sun lotion (this is not optional!)
- Hand wipes (the wet kind) so you can sort of wash your hands on-the-go
- The rain cover for camera mentioned by Caroline above. A 2-euro "single-use" rain poncho will do (just put the lens through the hood (secure with a rubber band to the lens hood) and operate the camera from below) - at least if you have a weather sealed lens.

This year I'm aiming to photograph the six largest open air festivals in Finland, looking good sofar acreditation-wise.

hand wipes and sun lotion are a must have at every festival, with or without camera ;D I always get sunburnt haha
another good tip for that is always drink enough (water or mostly non alcoholic beverages, I cant take pics while drunk )

good luck! I wanted to go to Tuska this year but I dont have enough money for that now... well there are enough cool festivals around :) lets start a festival thread hehe

Not too excited about Tuska this year (Provinssirock and Ruisrock are top-2 for me - I'll tell you more about them in the upcoming festival thread :)). Pity that you don't have enough money this year, it's always fun to meet new people that share the passion...

When I shoot bands I mostly have access to production office or somewhere I can park my laptop, plug in a cardreader and then have unlimited resources for shooting. Just swap cards over between laptop and camera.

So my bags are two. I'm working on it becoming one so that I won't need two bags to carry the following:

MacBook Pro + charger
x in one card reader + cable
350D
17-55 kitlens
50-200 old eos zoom
a couple of sharpies
a notebook
spare lanyard for lammies
torch
disposable earplugs

What I want in there is to exchange the 2 lenses for a 70-200 f/2.8 and a 50 f/1.8 and a wideangle and add a 20D or a 30D.

What I carry on concerts:
do not like any big bags, so I carry a small (but enough for 80-200 apart from camera) Tamrac Explorer II bag, w/camera with small lens and 80-200 apart. This is small enough, really easy to carry around when photo job is finished and I just want to see the rest of the show. Normally it's 4Gb SD card in camera and 2 Gb spare. Both are "Transcend 150x". Recently bought (Hullut pa"iva"t in Stockmann, finnish residents ;) cheap 1Gb SD slow cards just in case (9 eur/piece), but 6Gb is pretty much ok for every singe occasion.

Actually, this is only one bag I use for normal life. additional lens carried separately in its own case, so the SB-800 speedlight. From other things - lenspen, polarizer, tiny SD-card reader.

If I go for a trip, I use Lowepro CompuRower AW, but it appears quite heavy backpack. They got lighter and smaller model. It is ok for my three lenses and a body, relevant charger, laptop and its accessories. I like to use mini-tripod, which is good enough to take along when you do not know if you will need tripod or not, sort of compromise. Customs in Helsinki Vantaa Airport are always happy to see me with all my gear.

Still got to have spare accumilator and some filters...

LowePro Orion Trekker II for clubs/gigs:

-Nikon D200
-17-55 F2.8+hood
-50 F1.8
-SB-800 + spare batteries
-flash TTL hot-shoe cable
-MB-D200 battery grip (loaded with 2 NiMh batts)
-mem cards, lens clothe, aspirin (haha)

Promo shoot (large Crumpler bag+small sports bag)
-Mac powerbook + charger
-Nikon D50 back-up body
-2 airlift light stands, double-fold umbrella's
-manfroto tripod

I rarely shoot large enough venues that i cannot easily cover with the wide lense, currently tossing whether to get a 70-200 F2.8 or 85mm F1.4/F1.8... also have my eye on the 10.5mm F2.8 fisheye ;)

I rarely shoot large enough venues that i cannot easily cover with the wide lense, currently tossing whether to get a 70-200 F2.8 or 85mm F1.4/F1.8... also have my eye on the 10.5mm F2.8 fisheye ;)

I have 70-200 and 85/1.8 in my gig set and use definately 85 more (actually last night I left 70-200 home and used 85 and 17-55 only).
Since you have 17-55/2.8 and 50/1.8, you can come to conclusion which you need, speed or reach.

ideally, both ;D

depends on money, if i have the cash to spare after tax time for the 70-200 i'm going to get it. only because i wont have that amount of money to spare for at least another year. ha. plus it'd be great for portraits and the bokeh on the Nikon 70-200 F2.8 VR is pretty much to die for...

the 85mm, while still not cheap wont break the bank like the 70-200, so i could pick up in a few months if i save a bit.

My main body is a Nikon F100 with AF24-85mm f2.8-4 but I also use a Hasselblad Xpan II with 45mm and 90mm lenses when ever possible. Occasionally I'll have my back up camera (another F100) equipped with an 85mm f1.8 Nikkor or 50mm f1.8 . I've just started shooting with a Bessa rangefinder with 35mm f2 lens but I'm on the lookout for a Leica M6 if anybody is looking to sell one let me know!!

All wrapped up in a Lowepro Case.

General club shoot:
Small Tamarc shoulderbag
Nikon D200
17-35 F2.8 ED
24-70 F2.8 ED
2x4GB Sandisk extreme IV
1 SB 800

Festival shoot (only doning one two week festival this year, I get an Office though):
Nikon D200
Nikon D2x
Hassleblad H3d - 31 with 80mm F4 Lens (got some bandshoots and promo stuff coming up there)
17-35 F2.8 ED
24-70 F2.8 ED
80-200 F2.8 ED
2x Teleconverter
No Use for primes as there is plenty of light
Memory Cards (approx 12Gb)
2x Sb 800
Elinchrom Umbrella and light stands
Light modifiers (snoots, grids, softbox, Reflectors)
Metz flash
Mac powerbook
Mac G4 with 19" screen
Card reader
500 GB Harddrive
Backup Drive
All Chargers
Batteries
Lens cases for belt mount
Sunscreen
Pass houlder
Pens
Earplugs
Paper
Empty CDs
Business Cards
Office Keys!!!!!

Guess thats It

Canon 20D
Sigma 24-70 2.8
Sigma 70-200 2.8
Canon 50 1.8
Canon 15 2.8 Fisheye
Sigma EF500 Flash
Sigma 70-300 4-5.6
Dell Inspiron Laptop
Battery Charger
Ear Plugs
Lens cleaners
Spare batteries for flash
colored filters for flash
Assorted memory cards
Lanyard/credential holder
Condoms

I always carry 2 x Nikon D90s, both with MB-D80 battery packs

For local shoots I'll carry the following lenses:

Tokina 11-16mm f2.8 AT-X

Sigma 28-70mm f2.8 EX

Nikkor 80-200mm f2.8D ED

In addition I'll have an SB-800 Speedlight with SD-8 battery pack, a Gary Fong Lightsphere and a small Lumiquest diffuser for the pop-up flash. Spare batteries, extra cards, lens wipes & brushes, earplugs, pens, paper, business cards, clear plastic pouch & lanyard and a small torch make up the rest of the kit. This all fits in a 25 year old Billingham bag (don't ask which one... I have no idea).

If shooting at a festival I'll also bring a Sigma 135-400mm f4.5 APO DG and a monopod

All this equipment is then put in a Hama Defender 220 bag which will also house my 12" MacBook and battery chargers, a 2ltr bottle of water and a pac-a-mac