Thanks everyone for the replies!
I realise that, it's a big part of the reason I am considering switching - I never really got round to buying new DS games as 30 pounds is quite a lot to drop, but there are lots of SNES and other retro games I like. Portable video is good too.
I did have a DS, but screen brightness kind of killed it for me. That thing is just plain unuseable outside, or even in the car.
I'm considering getting a gp2x, but I'd like to know what the screen's like first. How does it compare to the DS? Can you see it easily outside?
Thanks! :)