Bought one last week, had not had time to log it until now. It was not so much planned and maybe a bit more of an impulse buy. Something like a cellphone conversation with my brother who's standing in a store in Singapore pressuring me with "Well? Should I buy one or not?" I don't like pressure, so obviously I just said, "Ok, whatever!"
The inevitable question arises: which one is better, PSP or NDS? A friend asked me if they have different types of games, and I tell her that the NDS has more fun/casual games, while the PSP has more action-oriented stuff. So I guess it really depends on your taste.
The NDS is a fun piece of equipment and I had enjoyed it so much I bought a 2nd one when I saw a cheap price, yet lately the PSP has been garnering more attention from me. Two obvious reasons: (a) it's new and (b) Final Fantasy Tactics, most likely my favorite game of all time is available on the PSP with rewritten dialogue, added characters and added battles. Whether it's better than the NDS in the long run is hard to say, as Ace Attorney 4 -- Apollo Justice lies in the short distance.
Also, the presence of Street Fighter Alpha 3 Max on the PSP, along with the inevitable need to learn Tekken: Dark Resurrection so I can beat up the guys at work is a strong incentive to buy a 2nd PSP. But I'm not that rich/impulsive. Not yet.
After the end of the lifetime of the PS2, I had been thinking that I may never again play console-style long games in the vein of Final Fantasy, but the PSP can possibly bring me back into that fold. PSX-style games on a handheld is huge, as one of the biggest drawbacks of playing on a console was needing to be stuck in front of a television to play those games. Amusingly, most of the games I have on the PSP now are ports/remakes of Playstation-era (or earlier!) games, which shows my preference for older games. I'm not even aware of what other games are available now -- FF Tactics takes up way too much of my mindspace.
I need to go play some more...