Agreed with everyone else: TV preview in the upper-right corner, but I'd rather have more room for larger fonts and a readable description of the show than have a preview. I can always turn on the TV in the background.
Two suggestions: for almost every skin, the most annoying sections of the EPG are consistently the title of the show in the description (there's nothing wrong with large fonts!) and the time row at the top of the guide. Make those work and I guarantee you'll get my vote.