Naa mate. don't do it,
I've had a PSP for nearly 2 months and its much much better,
theres a really nerdy gamer at school who has had the DS for about 5 months and the PSP for nearly 3 months and he hasn't bothred with the DS since he got the PSP..(and he's a massive Nintendo fan)
IMO the PSP is much better, sure the Nintendo has a histroy of good quality gaming, but they are still living in the past with the new DS.
The psp is better in everyway possible, so if your gonna plump for one at all, go with the PSP.
However, if you simply want to play the old games, on an old format, at a pretty similar old style quality, then you might as-well get the DS.
p.s, i've had loads of fun at school with my PSP, being able to show people trials videos, and watch South Park and Futurama whereever i want is great. :(