What Should I Get a PSP or a Nintendo DS Lite?

I want to know what would keep me busy longer a Nintendo DS or a PSP? I'm going on a very long car trip and need a handheld videogame so I don't get bored. I don't care about price, and I know what they both cost. I always carry a Ipod with me. I'm 14 and i'm going on a really long car ride and need a handheld to play with on the trip. I need something where I can play 5 hours on. Also, I was wondering if movies cost money. Probably. But, I wouldn't like watching movies on that little screen. Anyway, I like exiting, action games. Also, for my 11 year old little brother what should I get PSP or DS? The main thing, what would be more intertaining and keep me busy for longer.