3. Plants vs. Zombies (PC, iOS, PSN, XBLA, Nintendo DS)
You saw this one coming, didn't you? PopCap's relentlessly quirky defense game is nothing short of addictive, and is as fun as they come. We can still remember the first time we giggled at Crazy Dave's garbled gibberish, cried with our wounded Wall-nut as he fell to the hoard, and laughed at the (literally) mindless notes passed on from our would-be brain munchers.
But what good would all that charisma be without an airtight game to back it up? Plants vs. Zombies does away with the mazelike paths of other tower defense games for just a few short rows, minimizing the play field without losing any of its depth. The perfect balance between economy, fire support, and barriers is always in flux, with different scenarios calling for a unique combination of the various militaristic plants. And that's to say nothing of the minigames, puzzles, survival mode, zen garden, and other bits and pieces that make PvZ, without a doubt, an extremely solid package.