What Lisp dialect should I learn?
nostrademons: Honestly, I'd start with Scheme, because it's a small language and will teach you the basics of Lisp-like languages.  Once you understand closures, and macros, and continuations, and data abstraction in Lisp-like languages, and how you can build just about anything out of these building blocks, then you can learn the more advanced stuff that Clojure or Common Lisp has.For implementations, I'd probably start with PLT Scheme for learning.  It's fairly complete and easy to get up and running with.  Some other implementations are faster (Stalin), and some may have more practical libraries (Bigloo, though that's debatable), and some may have more interesting implementations (Chicken), but PLT's a fairly well-rounded early choice.  (Disclaimer: I started with Bigloo and my experience with PLT is limited to getting Arc to compile on MzScheme.)