Max For Live is going to open a lot of door for Ableton Live users - as this video by Matthew Davidson demonstrates.
In the video, Davidson uses the Monome to control OBO, his Max version of the ToneMatrix synth/sequence:
I've adapted obo for use in maxforlive, added monome 128/256 support (not required for operation), 16 pattern memory, edit while play, copy/paste patterns and a scale generator.
Interesting stuff - and Max For Live isn't even out yet!
Check out the resources below if you're interested in using Max For Live with matrix controllers.
DA-6400dp and US-20x20 to be precise
Load and play entire songs and automate effect changes