Correct me if I am wrong here, but isn't 1155 a generation older than 1366 and the Z68 is a generation older than X58?
Sounds more like a step backwards than a step forwards.
I would not do what you were considering in the same position.
If you want to go up from there, think about waiting until the Ivy Bridge processors come out and getting one of those instead.
1366 came out then 1156 then 1155 now 2011. Crazy Intel sockets.
I agree with waiting on Ivy Bridge. 2500K is an amazing processor but that 930 is no slouch. If anything overclock the 930 to ~4Ghz and wait a few months to see how good Ivy is going to be.