I actually own both theDS, and the PSP. I love both as both have many good games. I agree the PSP does have a bunch of ports, but some of those are GREAT. I am currently playing Disgaea on the PSP, and the new Advance Wars on the DS. The thing that bothers me is that sooooooo many people think that the DSis sooooo inovative just because of the touch screen. Yes it is a great idea, but underutalized on many games, and just tacked on for show in a lot of others. I buy systems for games, and both systems do have a lot of good games.
BTW..for those who feel the PSP has PS1 level graphics, you need to put some real time in with the system. Final Fantasy Crisis Core, Disgaea, Jeanna D'Arc, Brave Story....all gourgeous. There are MASSIVE differences in graphics between the two (not that is the end all be all).
My DS gets almost equal play time vs. my PSP. I love both, and as long as games I want to play come out, I buy them regardless of system