Though I've spent a lot of time before getting familiar with Common Lisp, I'm doing most of my hacking in Emacs Lisp these days.
I honestly prefer the way Elisp and feels does things in some ways over CL, and my ideal Lisp would be somewhere between the two (maybe I'm just talking Lisp Machine Lisp without even knowing it!). Having said that, they're already very close, and the cl-lib extensions give it an enormous amount of power with its macros and CLOS implementation.