I have to use audio units - a lot of those are VST only. - I'm pretty sure I would like the variety of sound stuff.
I have a few of those installed. The only one I really use is Voxengo Span. I have used Green Oak Crystal a lot, but I don't make that kind of music, so I'm just messing around with it. I've used it to put background noise into songs.
Not on the list is bx_cleansweep - I use the crap out of that one.