If I'm not mistaken, wasn't Halo a launch title? Meaning that it had a solid title from the start. I have yet to buy a PSP due to lack of games, but I bet GTA will make me get one. The DS was horrible when it launched, but now all sorts of solid titles are coming out, Kirby Canvas Curse just came out then you have...Nintendogs, Advance Wars, The new SMB, Castlevania, Mario Kart, Metroid, and Animal Crossing, all coming out before the holidays. Very rarely to systems have a load of killer titles right out of the gate.
I hope we see a price drop around X-mas time and I'll probably pick that good ole PSP up.
I could have sold my DS when things weren't going good for it, but then I would be feeling like a total douchebag right now. I'm pretty sure you'll end up feeling stupid for this in a few months.