It can be a small one, but choose a PSU that has full range active PFC (aren't all in the EU like that now?) and 80+ certification. That Antec Basiq isn't bad, but it is the only Antec I know of that has received only mediocre reviews. An Earthwatts would be better; the newest ones are 80+ bronze. The 380W model would be enough for you. Of the choices you listed, I'd get the Corsair, hands down.