The Thermalright Venomous X is one of the best air coolers you can get. They're reasonably well priced, and my one does a great job of keeping my i7 cool. They also work on socket 1366/1155/1156 setups as well so you can put it onto your next Intel build (provided Intel doesn't change the mounting system).
The only thing I don't like about mine is that the fan mounts are rather poorly designed, but it still does the job quite well.
If your budget doesn't allow for one of these, then have a look at the Cooler Master 212+. They're not as good as a high end air cooler, but they are quite cheap and should do a decent job of keeping it cool.
Another cooler worth looking at is the Prolimatech Megahalems or Super Mega.
This is not an exhaustive list of all the best air coolers, but it will at least give you some idea what to look for.