[quote name='AvidWriter']I never had a GBA [/quote]
Actually, you're probably better off getting a GBA SP because it's compatible with all the original Game Boy and Game Boy Color games as well as GBA titles. You can find plenty of excellent older titles (even GBA games) for cheap now. There are only a limited number DS titles available at this point, and they're all still fairly pricey.
You might want to get a GBA this year while you wait for the inevitable DS price drop (probably later this year or sometime next year). You'll definitely save money that way.