I'm running mainly reused old LGA775/AM2 stuff, except the ITX box with that uber 1337 keyboard. Didn't had to buy anything besides GPUs and two cheapo Celeron Ds (underclocked to 2 GHz / 1,1 V).

5830, 5770, XP 32:

http://img15.imageshack.us/img15/1835/rig1h.jpg

5770, 5750, 5830, Natty x32:

http://img810.imageshack.us/img810/172/rig2h.jpg

5750, doing some server stuff too, Wheezy x64:

http://img171.imageshack.us/img171/551/rig3.jpg

5750, 5770, Wheezy x64:

http://img9.imageshack.us/img9/3826/rig4g.jpg

I promise, I'll buy some decent cases if this still gives some profit in 3-4 weeks.