how much you willing to spend?
depending on your ram configuration (tall ram heatspeaders get in way of some coolers sometimes.) you could fit most things with in reason it looks like
cheap end Hyper212+ ($25~ish) (this is what I have with my overclocked I5-2500K (4.3Ghz ) I get temps in the 50Cs in games and 70C~ish running LinX for stablity testing) with 2x Gelid Silent 12 PWM fans
(i found the stock fan pretty annoying at higher rpms so i replaced it w/ the two Gelid fans.
there is the Hyper 212 Evo $34 (new and improved apparently hyper212)
the Corsair A70 is $28~ish after a rebate on newegg right now.
you could also get a Closed loop water cooling thing
like the corsair H60 or the H100(looks like the h100 would fit the top fan slots of that case?? (i think... but you might wanna double check) or other corsair H series coolers or the Antec ones..
you could get a higher end air cooler like the
Noctua NH-U12P SE2 http://www.newegg.com/Product/Product.a ... 6835608014
for that matter you could go nutz and build a custom Water cooling loop just figure on $350~ish or so for that (could be $$$ more could be a bit less...depending .. you could probably basically spend as much as you wanted if you go that way)
if it was me (and it was
) I'd get a hyper 212+ or Evo and call it a day... there are better coolers but for the money the hyper212 does a bang up job.