if youve got the time the akai mpd24 can be used with any daw and vsts its brilliant too use too.for creating beats with a laptop on the go youd be hard pressed to get a better controller at the price there going for now.
Akai MPD24 Velocity-Sensitive Pad Controller at DV247.COM
there also better made than the m-audio/korg pad controllers so can take some hammering out and about.
heres a video of it in action --
YouTube - Making a beat with an Akai MPD 24 - Its Alright by DJAJ