I'd recommend Clojure for two reasons: You'll get experience with functional programming, and you'll be introduced to the JVM at the same time. If you learn Clojure and later want to learn another JVM language, you'll be halfway there.
My past attempts at understanding Clojure have failed badly. (I must say I didn't try that hard, though.) Would a foundation in Lisp make it easier to learn Clojure?
Nah. Find a good book though, like The Joy of Clojure or Programming Clojure to get you through the fundamental bits.