I'd like to see a fuller line of Macs. Kaidomac's 12" MBP and the desktop cwa referred to would be terrific additions. I think they've pared down the options a bit too thinly!
I think a 12" MacBook Pro and an upgradeable mid-line tower would be the perfect additions to the Mac family. There really wouldn't be any holes after that - there is the cheap intro Mac (the Mini), the cheap intro laptop (MacBook, plus maybe a 15" inexpensive MacBook), mid-range line (17/20/24" iMacs & upgradeable Mac "Tower"), and the professional range (12/15/17" MacBook Pro laptop & Mac Pro desktop). Now that I think about it, a 15" MacBook would make sense since I know a lot of people would like a larger screen but don't want to shell out $2,000+ for a 15" MacBook Pro.