If you can do a bit over 500, say 570ish id recommend this build. you get the nice CPU and MOBO, which the mobo can unlock the CPU's 4th core and i personally have this CPU OC'ed 3.4 GHZ with the 4th core unlocked on air with load temps being around 50-52C. Also this ram CAS latency is 7, which is better, and easily OC'able. I tied my timings to the specs they gave though, 7-7-7-21 @ 1333.
Comes to 515 for all of those, and then add the f3 spinpoint.
Of course if you cant pull out the extra 70, id recommend a different GPU, the one listed should easily handle nearly all games at 1650 resolution . But it would still be a nice buy if you can afford it.
The 435 CPU I listed above would probably be as good or slightly better than the 630 for games right now, but it would give you a very nice, affordable quad core that should last you a couple years at least. The difference in gaming would be barely noticeable I'd guess--I haven't looked at any benchmarks. I think I would rather go with the quad over a triple core if you're planning on not upgrading the CPU for 2-3 years. I don't think the 630 is a great overclocker, but you should be able to get it up around 3.2 ghz with no problem on the stock cooler. The ASRock mobo won't be great for crossfiring if you want to do that down the road. But it should be a good enough board and it fits nicely in your budget. With that CPU/GPU combo, you should be able to play most games with high settings at your intended resolution.
The reason I recommended the 5770 is lower power consumption, lower heat, and it should outperform the GPU you listed, which is basically a scaled back 4870 (I think?). And you already have a solid 500 watt PSU, so you should be able to run that setup at well below your PSU's capacity. If you wanted to crossfire in the future, or add significantly to your system, you may need to upgrade to a more powerful PSU down the road. But that Antec should run a 630/5770 with plenty of wattage to spare.