I haven't had this much fun in a while. Originally I got it so I could play GBA games (backwards compatible) with a brighter screen.
Man was I in for a treat. The DS Library is huuuuge. Quality games. And creative games using the stylus.
RPGs, strategy games, adventure, dungeon crawl, it's got it all.
Chrono Trigger, Dragon Warrior IV, Hotel Dusk, and my recent favorite: Shin Megami Tensei: Strange Journey. I could play this game forever..
The DS Lite makes me fall in love with gaming again.