I'm hunting around for a 'verb for my 6505, and came across this:
[VIDEO]http://www.youtube.com/watch?v=5FsOysUoZzI]Holy Grail - Demo by Peter Stroud - Reverb - YouTube[/VIDEO]
I don't use much reverb with the amp at all - just a tiny spring reverb here and there to smooth the tone out for jamming and leads. I had the Strymon BlueSky before, and it was AMAZING, but completely wasted on my rig.
This thing, for under $100, sounds pretty damn good.
One warning: It is somewhat noisy, and you have to make sure your effects loop level is not too hot for it.