If it is only the front fan that gets in the way, just mount the fan a few notches higher. Otherwise look at Coolermaster, Noctua, Prolimatech, Scythe or ThermalRight. There are numerous alternatives.
I have your sitution and am using the COOLER MASTER Hyper 212 Plus for only $30 it is ideal and check out my (BillG) overclocking on PPBM5 I am using the second optional fan and do have the G.Skill fan installed on my Trident plus Turbulence RAM modules.
Bill, I bought the cooler you recommended
and it fits fine. Thank you. I checked the specs on some of the bigger coolers and none came close.I also entertained buying the CoolerMaste H70 too noisy or the H50. but didn't think blowing warm air into the case was a good idea. For those with tall RAM sticks make sure it all fits. There aren't many air cooled options out there for tall sticks. Thanks Bill.