Having some decent games would be a great start, though it's possible I've missed one in the year that mine has been sitting. 
Huge waste of potential.
I agree, I was sorting out my gadget closet and noticed my two PSPs in there. I must have 50 games I haven't played yet.
There is no appeal of lugging a heavy portable around. so I would make it smaller and lighter than the new slim models. A hard drive would be welcome too.