there's nothing wrong with starting with common lisp.
You said the thing that I couldn't express myself. I always had the image that Common Lisp was the advanced user's choice.
I'll setup SLIME right now to start with Common Lisp. Thanks!
It's not a bad thing to do, but keep in mind that SICP is not about Scheme and, despite including several Scheme-like interpreters and a compiler, it does not cover the whole of the language. Most notably missing are macros and call/cc.
So I think I'll postpone my read... again.
Thanks for all of you!