brenda. Render on Amazon AWS compute cloud off hours with spot pricing for dirt cheap. Not that the OP used this (I don't know), but if you need to render an animation on the cheap this will do it at up to 90% below demand pricing.
OP: have you checked out Radium? A kind of tracker that has some cool microtonal and microtempo features. Also FOSS.
http://users.notam02.no/~kjetism/radium/index.php
ever tried radium?
not strictly a tracker. but anyone who has used trackers should be able to use radium's tracker-like sequencer pretty easily.
it takes a liitle getting used to, but it's very powerful.
I run Linux on everything now, but if the majority of your PC use is for audio/music, I'd stick with Windows.
But on the Linux options...
Free
Both of the above crash a lot for me.
Commercial
There's also Radium tracker - which looks really promising. Still a tracker-like interface, but with a modern graphical twist. But still in heavy development, so bugs expected, and there's no decent documentation or anything. You need to pay for binaries, but can compile it yourself. I had it working from AUR for a while, but can't get it to compile now due to dependencies on old libraries.
Radium sure looks good: http://users.notam02.no/~kjetism/radium/
PlanetCCRMA used to be a reasonable distribution but I'm not sure it's still maintained: http://ccrma.stanford.edu/planetccrma/software/