I like Aero, it just makes it nicer to do boring things!
However, I usually turn it off when in certain applications that use high resources. I right click on the shortcut and then check "disable desktop composition" under compatibility.
I have it set for Visual Studio and a few graphics applications.
That being said, anyone used compiz-fusion on Linux? That is just amazing... I have so many funky and good effects on a old p3 with rubbish graphics! - http://www.youtube.com/watch?v=E4Fbk52Mk1w -
it is brilliant! I wish someone ported it to Windows!