I've been looking into this as well, and I still can't see a reason to upgrade. The steady march of games needing more power has slowed, because every game needs to work on consoles, so there's no push from that direction. I could go Sandybridge-E to get two more cores, with a slightly better o/c (my 1920 is at 4.2GHz), but at the cost of a big increase in leccie consumption - and my utility bills are already £120 a month. Or I could go normal Sandybridge and get a much better overclock and lower bills, but for little extra gain in performance. Or I could wait for Ivybridge, which just seems to be Sandybridge with better peripheral support.
I'd like to upgrade, but I really can't see what I'd gain that would be worth the expense.
M