[eliben]

Unless you plan to switch your projects to a Lisp (by which I mean a general name for CL or Scheme) right away, I would recommend the following route:

1. Start with PLT Scheme/Racket. It's self contained, very well supported on all platforms, and Scheme is a leaner and cleaner language that will cause you less confusion in the beginning. This platform should be enough for you to learn Lisp and be enlightened by its idioms.

2. If in the future you plan to get serious with Lisp and write real projects in it, reconsider. You will have much more familiarity with the eco-system by then. Scheme vs. Common Lisp is a religious war of epic (= brace style) proportions, and it's not wise to get confused by it right when you start.