Yeah. You can't choose between a portable system and a console system. The console will always have better, bigger, and a greater number of games (unless it's the GameCube, first to break tradition).
Right now, the PSP library is very weak, like most newly launched systems. The advantage of buying now is the possibility that if you got a 1.50, you could run homebrew, and potential 1000's of classic games.
I hate buying systems at launch. I've done it 3 times. First with the N64. for 4 months I owned half the entire N64 library of games. Then a third game came out.
PS2, I had Tekken Tag, and that was it. Eventually I got Oni, and said it was awesome, just because it was my other game. I look back today, not so good.
PSP has Wipeout. If you are a fan of the series, and were upset with Wipeout fusion like I was, this game is very refreshing. There's not much else. I got NFSU Rivals, and it's fun, but it's not Underground 2.
...I'd love to see a wipeout at PS3's release...