ACID Xpress sucks hairy ass. I recently downloaded it just to see how it works. and it really pisses me off how little control I actually have over sequencing and other stuff. I gave up after a few days trying it out.
seriously, there is probably 2 freewares that are actually good, Protool Free and Super collider.
but looking at zyberdaddy's situation, Ableton live should be a good software to look into.
http://www.ableton.com/index.php?main=news