The Rhythm Is Gonna Get You
If shaking your groove thing or laying your thing down is something you enjoy, you might be interested in Gamespot's Rhythm Game 10 Spot, looking at the 10 Best Rhythm games. From the article: "Some of these rhythm games never made it outside of Japan, and others require you to purchase an expensive peripheral controller, but all of the greatest rhythm games are characterized by a few elements--a noteworthy soundtrack, a unique method of interaction, and an addictive gameplay. To be truly great, the game can be responsible for pioneering the genre or merely perfecting the established formula, and whether you're using your feet, hands, or stylus to map out the beat, we guarantee that in the following 10 games, the rhythm is going to get you." Played Guitar Hero for the first time this weekend, and it is as good as everyone says it is. Highly recommended.
Though frequency is an awesome game in its own right, they fixed a lot of the awkwardness of the game with Amplitude. It's the same game, but with some of the more frustrating features removed (like tracks only being cleared until checkpoints).
Have you tried any of the more hardcore rhythm games? DDR/In the Grove are far from easy. If they aren't your style take a look at Beatmania IIDX, It's coming out in North America in march I believe, it's supposedly one of the most insane difficult rhythm games in existance. Stuff like Guitar Hero, donky conga, etc tend to be pretty tame.
That is of course, GTA: San Andreas Hot Coffee Mod!
They didn't even mention Donkey Konga/Donkey Konga 2 or Taiko Drum Master on their list. (OK, they're on the vote thing at the end, but not mentioned in the article!) :)
Anyway, as a drummer, I was drawn to the Donkey Konga games, and liked them as much as I expected. As for TDM, I've been wanting to get it, I'm still just waiting for the funds to be available for it