Slightly tangential, but I wish some Lisp would make a serious comeback and challenge mainstream languages. For this purpose, libraries are essential. So better tooling would help, and that's why Ultralisp and Quicklisp are interesting.
Clojure is very nice. I have used it for several projects. But sometimes I would prefer not to rely on Java libraries so much, and cleaner stack traces.
Racket may get some critical momentum now, with the whole merge with Chez.
I don't have high hopes for a Common Lisp implementation, as the ecosystem has become too fragmented and stagnant. But I wish I could be surprised here. Shen introduced some great ideas to make a powerful static typing an option in Lisp [1].
Re statically typed Lisp, I’m keeping an eye on Carp [1] which seems to be a quite active project.