Apparently, the best overclocker right now is Core i5-2500K. It has 6MB L3 cache and runs at 3.3 GHz by default and can be overclocked via unlocked multiplier up to 4.6-4.8 GHz on air in average. It costs about $210, as far as I remember =) If you want a Core i7, the best overclocker there is i7-2600K, which has 8MB cache and runs at 3.4 GHz by default and overclocks a bit higher than i5-2500K. It also has hyperthreading, which i5-2500K doesn't have, which is good for video encoding and 3D design (if you have applications that benefit from hyperthreading!), but useless for gaming. 2600k costs about $100 more than i5-2500K. If you're planning to do just gaming, go with i5-2500K, if you plan to do more professional work as well, go with i7-2600K.