You have a nice processor, if you complain about the Q9650 heat dissipation, you gotta see how much heat the QX6850 can dissipate at same overclocked speed, it used to warm my whole room in less than 10 minutes, moving to your same CPU cut the heat dissipation in half running even at higher speeds. (QX6850 ran at 3.60GHz and my Q9650 ran at 3.82GHz)
An i7 920 runs as fast as the Q9650 mildly overclocked to 3.20GHz, so moving to an i5 even when overclocked will be a sidegrade or a minor upgrade with the same heat dissipation. Current Nehalem/Lynnfield architecture uses lots of power when loaded, so unless if you go to a power efficient Intel CPU or an AMD 45W Quad Core, your processor is the best you can get for now until a new architecture arrives (Sandy Bridge or Bulldozer)