I have sevral bags, all more or less ready to go :

35mm : Lowepro Nature Trekker with
- EOS3 body with BPE2
- EF85/1.8 on the body
- EF24.2.8
- EF50/1.8 II
- Extension rings
- Remote cable
- "Standard" grip + 2 batteries (got caught in the field several times with the LR6 dead in the BPE2)
- Lens cleaning kit
- 550EX flash (I tend to get it out of the bag before leaving, maybe I should consider getting rid of it)
- Sigma 300/4 EX/HSM (Again,it stays home most of the time, I should consider getting rid of it)
4x5 : Lowepro Nova5 with
- Tachihara
- 75/8 Super Angulon
- 150/5.6 Apo Symmar
- Release cables
- Capital Spotmeter + spare battery
- 5 loaded holders
- Lens cleaning kit
- Various tables + metric tape

Filters fow B&W are in a separate pouch, with the holder and rings attached :
- Yellow filter
- Green filter
- Orange filter
- Red filter
- Pola filter
- Rings for all my lenses

MF : Nova micro with
- One camera (onlyt in the bag when I'm gonna use it, either Rolleiflex or Yashica
- Lens hood
- Filters
- Gossen Lunasix 2 (generally outsied the bag, I'm considering buying a smaller one