Ubunto and debian seem to work nice. Just be careful what drivers you use on your cards. trust me it makes a huge difference.
Ive actually found that windows works best cause the drivers and SDK are better. Im still messing around tho
No, don't even use Ubuntu. Unity is good, but it'll eat your resource (Unity is built in with compiz). But *buntu family like Xubuntu or Lubuntu is fine though.