Hey guys! I have FFIII and "The New"Mario Bros so far, and I am wanting to make a list of some of the "best" games for the DS that anyone should own...so list away. I myself prefer RPG and the Mario Games.
Not having a DS myself, I can't recommend games based on experience, but if I did have a DS, here's a short list of games I would seriously consider renting or buying:
Starfox Command
Mario Kart DS
Brain Age
Big Brain Academy
Brain Boost: Gamma Wave
Also, do you have broadband Internet and a wireless router? If so, you can play multiplayer games on your DS. That reason alone was nearly sufficient to tempt me into buying one, but I purchased a Playstation 2 instead since I'm content with my Gameboy Advance SP.
Speaking of which, since the DS plays GBA games, be sure to keep an eye out for Final Fantasy VI Advance, due out Feb. 5, 2007.