Software for Firing off one shots? (Mac)

So I just got a VCI-400, and am already in love with 4 deck mixing in Traktor, but my trouble is I use all 4 decks as track decks, and pretty much never use the loop recorder.

So I have no samples, and some spare midi space on the 400. I want to reassign those MIDI commands to control another piece of software (preferably lightweight, I've never used Ableton and it seems like overkill for this purpose!) just to fire off one shots.

Any suggestions? Running OS X Lion btw.

If you just want to play one-shots, any standalone drum machine could do it if it's not explicitly based on using an internal sequencer.

Motu makes one called BPM, which I've never used. NI makes Battery, which I don't like. IK Multimedia's SampleTank should work. iZotope iDrum…take your pick…

Thanks I'll have a play!