Great choice!!

350w-500w scooter motors are your best bet, dead cheap and easy to implement. You can get them bare, or with an attached gearbox (I'll be happy to PM you links to cheap ones). I personally use wheelchair motors which are plenty torquey enough, might try them on 36v for a little more speed this year. Speed controller-wise, we often go for the Cytron SmartDriveDuo 60, which has proven itself to be reliable enough on this scale. Batteries, I'm not a good example to follow, ended up using a 2800mAh NiCad after there wasn't room for another inside.... but it did the job for 3 minutes which is all you really need, probably gonna want a 6S LiPo over 4200mAh as Lucy said.

Good luck with it! Be sure to tell us how you get on