Since this a place for old games, I'm betting some may have pretty ancient hardware.
I'm probably a bit overpowered for this forum too, but uh, here goes:
PC 1:
Gtx 260
PC 2:
8800 gts 640
PC 3:
x1800 mobile
PC 4:
9600xt
PC 5:
Geforce 3
Unused:
X1900xt 512

Just the one active PC for me. I used to have an 8800 GTX, but it failed about 2 years after buying it. Thanks to BFG's lifetime warranty, they didn't bother to repair it, just sent me a lovely 8800 Ultra instead.

2X Nvidia 8800 GT's in SLI

I'm only running one PC and I have a Geforce 8600 GT. Not exactly a powerhouse but i haven't found a good enough reason to upgrade yet.

7600GT
Will probably get 9800 after Empire is release. First Ill see how it runs.

I have two PCs at home. The first one is from 1994 and I am not sure what kind of GPU it has. The second, my current one, had GeForce MX4400, but I switched to GeForce FX5200, and now I am using GeForce 7300GT. I am not planning to buy a new one, but if they ask me which one I would like, it would be the Sapphire 3850HD, simply because it is the best AGP card available.
But my next build/PC, the one that I am hoping to buy during the summer, looking at the situation right now, it will have Sapphire 4870HD. If nVidia and ATi release new cards later this year, I might skip the 4870HD and go with the new ones. I'll just have to wait and see.

I have too many PCs in different states of functionality and assembly to list, but the main and fully functioning PC I use currently has a 7600 GS.

Primary PC: 9800GTX1 (1GB)
Secondary PC: 6600GT (128MB)
Guest PC: GeForce4 440MX (128MB)
Backup PC: TNT2 (32MB)
Doorstop PC: Trident something watchamacallit (4MB)

Can only be bothered to mention this one, as it's probably the only that matters, and that is a HD4870 512MB. Before that was a X1950Pro 512MB.

Intel GMA945 on my netbook, Geforce Go 7600 on my main lappy & much the same on my media PC (Its a GF7 series onboard with a normal mobo)
I used to run a sweet Gainward 6800GT but the agp port in my game PC died and so I pretty muvch sold it off for parts since I'd have to replace everything but the HDDs to get it running again

Single 8800GT 512 MB.

One PC: NVIDIA GeForce 9800 GTX+ 512 MB

9600 GT in the primary PC.
Don't remember what's in the others and don't have time to look but they are all fairly recent (ie, within a year or two or initial release).

While there are three PCs in my house, only one of them is stationary, and I don't use those others since they're not really mine (my wife and daughter has one laptop each). So the stationary is the only one I use, and that carries a GeForce 9800GTX card, more than enough for the gaming that I do (I hate not being able to run games on max settings - that's one of the worst side effects of PCs, always being one step behind).

i have 2x geforce 9800 gtx in sli mode (makes supreme commander run well) :)