4. Dragon Quest Wars
There are a few online games available through DSiWare now, including Uno and Sujin Taisen. Unlike Uno, which feels like it had a development budget of around $5, and unlike Sujin Taisen, which has an online community of exactly zero, Dragon Quest Wars is both high quality, and popular online. Which is just as well, because the single player game is limited. Online, though, this basic board game shines, being highly strategic and the cute Dragon Quest critters gets it over the line.