Learning a Lisp

So I'd like to learn a Lisp. What dialect should I use? I believe Common Lisp is the most widely used one. And what about books, online tutorials?

Also, if you've never programmed before, there's another book you might want to consider:
Common Lisp: A Gentle Introduction to Symbolic Computation http://www.cs.cmu.edu/~dst/LispBook/
Altough, SICP fits that role rather nicely as well.