I think you have made your choice... I moved from an I7 950 (oc to 4.0) and am running a 4770k (at stock for now, not had time to play) and there is very very little difference in performance (in games at least)
Main reason for moving for me was heat and noise, My (then) gf needing a rig to do photo editing and graphic design on was the kicker that made me move.
Short version: If your happy with the 920, don't bother.
AKG: "So please don't piss on people and claim its raining. "
Soullessone21: "Their the only fat bitches I ever want in my wife :)"