Best answer selected by w0oter.
nIt seems you selected my original post as the "Best Answer" while I was in the middle of editing it.
nAnyway, like the original post stated the Athlon II X4 630 is not an ideal choice since the Phenom II X4 925 provides a little better performance for not much more money.
nThe Hyper 212+ heatsink as recommended by jjb8675309
is a good choice. It is very effective for the price that you pay.
nSure, there are better heatsinks around, but they also cost more.