CL isn't really functional, but you can write functional code in it without problems, it just depends on what style you prefer - CL doesn't force you into any particular style, you're free to choose. Scheme tries much harder to make it more likely you end up writing functional code, but doesn't force you either.
Haskell is purely functional.
less weird syntax
Lisp's syntax is fairly simple compared to Haskell's, but Haskell's syntax looks more 'natural'.
You should probably read SICP (which teaches you programming and uses R5RS Scheme, without macros), and eventually try your hand at CL (read Practial Common Lisp if you want a simple introduction with examples). If you end up prefering Scheme and want to use it for more practical programming, you'll end up using some popular implementation like Racket which provides many extensions/libraries. If you end up prefering CL, you can use the wide majority of implementations (such as SBCL, ClozureCL, ECL, CLISP and so on) as they follow the same standard and libraries tend to work interchangably (except those which are highly unportable, but most of them have compatibility layers which allow them to work with most implementations).
You should also learn ML or Haskell as well as they have their own unique lessons to teach which are not obvious in languages which are not staticly typed.