David sent a link to the 50D review. Reading it was helpful as an supplement to the dry user manual.
I noticed that the charger that I got with the body-only kit looks different than the one pictured in the review. I still don't know what the AF-ON button ("The AF-ON button allows you to trigger auto focus independently of the shutter release 'half-press'.") is supposed to do— pressing it seems to focus the lens far and then close in small steps— more reading required. Page 10 of the review has a movie that shows AF operating in LiveView mode. Perhaps it's not working for me because I always have the camera handheld rather than mounted on a tripod or stabilized. Page 17 has an interesting comparison of the sensor noise levels of the various cameras; the Nikon D300 is unexpectedly impressive at ISO1600.
Update Sat Nov 08 12:55:45 2008: After re-reading the LiveView chapter, I have a better understanding of the auto-focus in LiveView mode now and it does work (for some values of "work").
