Lisp resources
Peter Seibel has written a book called Practical Common Lisp, which is available in dead-tree form for money or online for free. From what I have seen, the book is excellent, to put in mildly. It shows how to get the most out of Lisp’s functional nature, and how to harness that power for everyday needs. For example, Siebel explains how to write a cgi script for editing the playlist of an Icecast-compatible streaming mp3 server — a project that I am actually interested in trying, but one that I would never have imagined would be easy to do in a notoriously antisocial environment like Lisp. CLTL teaches the grammar; On Lisp teaches how to think Lisp; and Siebel’s book teaches how to use Lisp in real life. All three should be read.
On a similar note: the λgtk project has produced a high-quality, non-beta, actually-maintained, and modern Gtk2 bindings for Common Lisp. For the first time in history, Lisp can be used to write a decent-looking gui.