Like many others, I'd like to see druids and psions, but most of all I long to see the necromancer class. My players and I both love necromancers. They make wonderful villains and interesting PCs, and it's unfortunate that -- assuming they stick to their "classes in PHBs only" and "one PHB per year" limits -- I'll have to wait until 2010 or even 2011 for the class.