$600 budget light gaming build, undecided!

I have already made a post here before but theres still a few things I haven't been able to decide on. My budget is $600 max, however I am wondering if it is really worth going up to that much for the type of games I play and for the time that I will have it. ( I am currently 17, still a year away from college.)

I only play some steam games and alot of different MMOs (mainly vindictus). I don't want to run BF3 on max settings, but I might want to be able just to play it. I also don't have an HD monitor so that shouldn't be a problem either. Here is what I have right now:

CPU: i5 2500k from microcenter $180
MOBO: Biostar TP67B+ $120 - $40 promo - $20 MIR = $60
RAM: G.Skill 2x2GB ddr3 1333 $40
PSU: Antec HCG 520W $55
Case: HAF 912 $55 amazon
GPU: EVGA GTX 460 $160

Total: $550

ALREADY HAVE KEYBOARD, MOUSE, OS, HDD, OPTICAL DRIVE


CPU I am pretty much set on, for $20 more its a big improvement over the i3

MOBO not to set on this mobo, I don't really need a top end $200 one, I don't think I need to go above $130 on it, since I also get the $40 off from the i5. I heard biostar was crap too, but microcenter doesn't carry asrock so that leaves me with gigabyte or MSI which I like. Also, not sure if I need a p67 or if H61/67 will be enough for me. I might try to overclock in a few months, but I don't plan on sli/xfire in this build.

RAM good to go

PSU good to go

Case: now there are alot of options in the $40-70 range, that's about what I am spending. The HAF 912 looks good, but I might have to buy more fans for it. I was wondering if its better to go with the antec 900 ($70 after MIR on newegg now) or NZXT apollo or something

GPU I was pretty set on the GTX 460 but looking at benchmarks the 6850 performs better? I want to be able to max out the games I play (vindictus, valve, source games mainly) so I need your guys opinion on this and which model.