Xeons handles a heavy and stressed enviroment work area. They're not the same as an i7 at all. They're more stable, that's all...
As for the i7, well, the 1156 series are more affordable, but in the 1366, a 920 is the best to get. A 940...eh..double for a bit more speed that you can obtain with a breeze on the 920...doesn't appeal me.