At the moment my setup is mostly the following
My bag (LowePro Minitrekker) holds the following:
Canon 400D+grip, Canon 70-200mm f2.8 IS, Sigma 150mm macro, Sigma 70mm macro, Sigma and Canon 1.4 TCs, Sigma 2*TC, Speedlite 580M2, Sunpack PF20XD, Lumiquest softbox, cable remote release, LED single bulb torch, memory cards, release plates for tripods, gloves, hat, small foldup waterproofs (trousers and top) Raynox DCR 250.
oh wait and the kit lens for my camera is in there somewhere too.
I then added a LowePro 60AW pouch to the side of the backpack and inside that I hold:
Len cleaning gear, Cir polarizers for the 70-200mm and 150mm lenses, Rocket Blower, mini ballhead, offcamera flashcord, small AA battery torch, screwdriver (for the tripod head screws), multicard reader and cable, OPTEch rainproof cover.
The rest of my gear rests in the slowly filling draw under my bed:
Canon 2*TC (I took this out of my main back in exchange for the 70mm macro, and whilst its a good teleconverter the sigma fits all my lenses whilst the canon only fits one - and both are used more rarely so no need to carry both at all times), Manfrotto 322RC2 head, focusing rail, 2 older Praktica film cameras with 50mm lenses attached and a single 28mm prime for the Prakticas, 2 old lightmeters, AAbatttery compartment for the battery grip, some other junk that I forget now......
My tripod and monopod mostly rest on the floor in a corner - I don't really have anywhere else to put them - the boxes for my gear also rest on top of a shelf - some inside each other as best I can to save on space
So in total its mostly all held in the backpack at the moment, though I do share the fear that the gear is growing and will onday spill everywhere! Mostly I just worry that I will need to get some case or container to store more lenses in as I get them and lose the abilty to carry most of them with me at all times