I just bought my own Christmas present, a Canon EOS 650D.
I must declare myself VERY satisfied of the purchase.
What I gained over my old 450D:
+ 50% more pixels (12MP to 18MP), which since I have all L optics, make a difference when cropping
+ wireless flash! no more horrible cables and manual modes!
+ a truckload of ISO (in theory up to 25600, and it's still very usable at ISO 6400). The 450D went up to 1600.
+ max SD card speed increased from 20MB/s to 95MB/s (and I shoot in bursts A LOT)
+ tiltable display (fundamental to shoot overhead in a crowd)
+ the shutter sound is somehow more muffled, less acute, and definitely more pleasant (the 450D sounds like TLAK TLAK TLAK; the 650D is instead CLOCK CLOCK CLOCK )
What doesn't convince me:
- tracking autofocus is still completely useless to shoot anything faster than a walking person - e.g. forget about catching birds in flight
- autofocus in live mode is sluggish and borderline unusable
- video mode. You MUST use IS to shoot handheld, and it's very noisy. Completely forget about autofocus (slow, inaccurate, unpredictable, and very very noisy): you'll need to manually focus all the time.