The Core i7-2600K & Core i5-2500K is AWESOME upgrade for most people, great job Intel. Not sure if I'm going to buy the overpriced Intel Extreme Edition again.
Waiting for the AMD Bulldozer to compare since I need complete platform upgrade anyway. Would rather give my money to AMD, they sure need it more plus I might save a lot.
Did read only the AnandTech review and the 2600K & i5-2500K is sure a big winner, to bad it's not upgrade option for me.
Here few quotes from AnandTech Final Words
Lynnfield took away a lot of the reason to buy an X58 system as it delivered most of the performance with much more affordable motherboards; Sandy Bridge all but puts the final nail in X58's coffin. Unless you're running a lot of heavily threaded applications, I would recommend a Core i7-2600K over even a Core i7-980X. While six cores are nice, you're better off pocketing the difference in cost and enjoying nearly the same performance across the board (if not better in many cases).
In all but the heaviest threaded applications, Sandy Bridge is the fastest chip on the block—and you get the performance at a fairly reasonable price. The Core i7-2600K is tempting at $317 but the Core i5-2500K is absolutely a steal at $216. You're getting nearly $999 worth of performance at roughly a quarter of the cost.