For a mainstream cooler the Corsair A50 does an exceptional job, and while it couldn’t quite match the cooling performance of the higher-end heatinks it does have a better price to performance ratio than that of the more expensive offerings.
Currently the Corsair A50 can be found for $35.24 shipped without a rebate and that should be able to fit any one's budget. For that you get a CPU cooler that works well at stock processor clock frequencies and even higher overclocks, and for $35 it makes for a nice upgrade over stock cooling.
So in this regard, A50 is ideal!
Cheers!