The Spyder3 Pro seems to be getting some good reviews, as do the Elite.
I bought myself a Spyder3 Pro a few days ago and must say there is a huge difference in how images look. It's definitely worth the money if you do editing or have multiple monitors.
As for the licensing, the license is for many computers in one physical location, as well as up to 5 laptops. See
http://forums.dpreview.com/forums/re...ssage=28248186 for some more details about this.