The best CPU based on price/performance is the i5-2500 (with or without the unlocked version). I suggest you should get the K (unlocked) version which costs only around $220 on newegg.
The i7-2600(k) has the same graphic (HD3000) as the i5. The i7 is just faster a little. Not that much a difference IMO.
I5-2500(k) or i7-2600(k) with MediaConverter7 or MediaExpresso utilizing QuickSync is the best video encoding solution you'll have for a very low price. I transcode a 10GB 1080p MKV 100 minutes to 5GB 1080p MP4 in 18 minutes. Awsome!
I know this topic is close, but i support that, the 2500 - 2600 K or non K are beasts, i proudly own the 2600k, i'm still don't do OC an still, is faster for every use i have, i usually play games like MW3, my wife see movies, I use DVD shrink and encode videos, and use jdownloader at the same time, and i wont see any freeze in my game or the movie, so unless you have 600 dollars for the new cheapest LGA2011 i7 this two are the best option, over evrething else in the market, in my opinion if you use multitask better use the 8 thread of the i7, instead the 4 thread of the i5