Is this PSU any good?/ Enough for my system

^+1. The little voltage switch gives it away as an older, inefficient design; almost certainly overrated.
A quality modern PSU has full range active PFC (no little voltage switch) and [some level of] 80+ certification for efficiency.
Seasonic, Antec, Corsair, Enermax, and XFX are among the better brands. A 500W Antec Earthwatts would be a nice choice.
 
Unless you're planning to add a second GTX460, 500W is all you need. The EA-500D is the one I was thinking. The ones beanoslim's link shows would do too, with the OCZ below the others. It has had good reviews, but dissection may indicate some sub-par items like 85C capacitors so I don't know that it would last as long as the others (still, we're talking years here, not weeks or months).