I actually wasn't kidding with Rock Band. The only drawbacks are the lack of a second bass pedal, and a pedal for the hi-hat. Other than that, you'll be exposed to drum beats from a variety of styles, developing hand-foot coordination, tempo, etc.
Rock Band is actually how I learned how to play drums. I couldn't play AT ALL on drums, then after playing Rock Band, I was able to play drums decently. I was at a jam with guys who played as a hobby, including some amateur drummers, and they kept asking me to do drums since I could play more complicated beats.