Top floor of the house! My den doubles as the bike storage room, as well. I have two desks, with three computers. The visible desk has my workstation (dual Xeon, 48GB RAM, bunch of SSDs) and a little linux box (core2quad, 16GB RAM, SSD) that I use for internal hosting/testing. I'm currently rocking three Dell 27" monitors - love the resolution I get to play with.
The second desk, not shown, has the "guest" computer - my old workstation. Also a dual Xeon, though only 16GB RAM - to make up for it, it has one of the OCZ RevoDrive cards.
And finally, I have a 17" MBP, 10.1" Samsung Galaxy Tab and my Galaxy Nexus for when I'm on the move.