AirWindows are a small seemingly Indy plug-in maker that churn out some of the best sounding stuff this side of very expensive things and other good stuff not very easily obtained.
Scroll down the page for a selction of free AUs, but I would also recommend checking out their commercial stuff ($30 to $60) of which most now come in demo form to try out.
Mac Only
P.S - Live set will be uploaded sooooon.