Also new is "a refined 3.0-inch Clear View LCD (920,000 dots) monitor, supercharged Live View Function with Face Detection Live mode, plus a number of new automatic Image Correction settings and HDMI output for viewing images on an HDTV."
There's also new sRAW settings, a new set-up for the sensor's micro-lenses, and Canon says the 50D has better environmental sealing than it's predecessor, the 40D.
I'm thinking what is more important may be in what is not emphasized by Canon. The 50D has pretty much the same AF system as the 40D. That leaves Canon's AF complaints unanswered, and certainly doesn't offer any competition for the Nikon D300's excellent AF system.
The 50D also doesn't appear to have wireless speedlite control, a valuable function that Nikon has had on most of it's cameras for some time now.
All in all, the 50D appears to be a fairly minor up-grade from the 40D. Sure it's got more mega-pixels, but do we really need them? Most pro's (including myself) will tell you that we don't need any more mega-pixels. Ten or twelve is more than enough already. Much more important would be for Canon to fix it's AF and QC issues.