Get a i5-3570k. Unlocked and great for gaming.
+1 for Headbomb
Right now most of the main stream or high end games are using around 3 threads (only a few are using more than this). Game programmers are getting multi-threaded performance by spliting the performance in to physic, graphics and sound. Hyper-threading is used last since it doesnt have the performance of the full core. So on an Intel Core i3 you might see the hyprer-threading being used more than you would on the Intel Core i7 since it has 4 full cores to be used first.