IE 6 issues

Looks like I need to move to IE6 to
accommodate some new software. I know
that there are people on this list who
understand security and also understand
Windows in a realistic way, so I'll ask
here.

Coming from the latest IE5 update, what
new issues should I be aware of with IE6?

It's getting closer to the time when I
will be wanting a separate machine for
the Windows addicts in my household, but
it's not in the cards right now.

Thanks,

Vic