[Flow]

Stick with Scheme for SICP.

As for the other Lisps, I think you should give them all a lengthy and serious try. It's worth it.

For Common Lisp, when you have learnt it a bit, get the book Let over Lambda. It's a great bus-ride read and, IMHO, is one of the best Lisp books I've read.

When you get to Clojure, don't be put off by the JVM and the harsh stack traces and unhelpful error messages. Look at the Rich Hickey video presentations and realize Clojure is its own thing. There are lots of smart and practical choices made in Clojure.

I've not had time to give Racket a try yet. But it seems a very nice language with good implementation, docs and community.