I personally run a big tyan server rig at home, though I also have a prolient dl385 blade server, the tyan is a big gpu parallel processing rig with a bunch of radeon 7950 pcie cards (and I dont just use it for folding at home
). But if you want something super reliable, old prolaient blade servers you can pick up bare bones pretty cheap, highly upgradable, AMD opterons are cheaper than xenons. Also you have this nifty ilo port (internal lights out) so you can boot it remotely and everything. EVERYTHING is redundant on those, form from fans to drives to power supply, I havent turned mine of in like 2 years lol