M$ get's no money from mac sales.
IE is included as part of a stock deal several years ago. M$ ownes a whole bunch of non-voteing Apple stock. So I spose, if you make apple richer M$ et's oney thrugh stocks... but M$ also owns stock in dreamworks, NBC, as well as several hardware manufaturers etc. So chances are you already end up paying M$ inderectly anyway.
This is a moot point. OSX is a solid OS, and like linux is very protected. For a program to leave running processes when you logout or restart it would need to somehow be wired up to the kernel.
If you are really paranoid about IE leaving files, open up System->librarys->Application Support and trash the prefs file.
That's it. IE is gone.
I use Chimera, put together by the mozilla grupe. Excelent browser.