Don't fool yourself into thinking that In-Win BUC is in any regards "small". Also, the reason I recommend it is because you
don't have to mess with it, it's a pleasure to work in. It's your decision, just don't hate on it too much.
A 600W power supply, even with what you're putting into it, will cover that with enormous room to spare. The only reason you'd ever have to go above 600W is if you're cramming it with TOP of the line multi-GPU crap, and some extra drives on top of it. Seriously. I have a Core 2 Duo overclocked to 4GHz, 6 (yes 6) inefficient hard drives, a decently power-hungry Radeon 4870, and accessory cards. Not to mention all my USB ports being filled. Even with all that, I don't think I've ever seen it pull 400W, much less anything near 600W. And that's measured from my UPS!
The real reason your PSU's likely died is because they were pieces of crap, not because you were putting too much on them. People buy 1000W PSUs thinking they need them, when in reality the only reason they need that high is because they're buying unreliable crap PSUs to start with.