As promised, James has just posted his Recovering Lost Code Screencast, which clearly demonstrates how powerful Smalltalk development environments are, and will give you a chance of seeing how VisualWorks looks like.
I must confess Smalltalk is deeply impressing me: i want one of those environments for Scheme! In the meantime, i content myself playing with Squeak, which has nothing to envy to VW, by the way. I used to complain about its looking childish. Besides silly, the complaint is baseless: see how my Squeak environment looks after installing the Skylark Theme…