Nintendo DS Lite or PSP?

Ok guys, I need your help so bad. I'm getting a PSP or a DS lite. I have NO IDEA. Which one to get. I'm not into the kiddie games, I like racing games, shooting games like rainbow six, you know. That kind of junk. lol My main issue would be I've heard the PSP has WAY better graphics than the DS lite. Is this true? I want something amazing, that will not disappoint me. I want something epic. Please help. Thanks in advance.