I've tried both Scala and Clojure recently, based on similar motivations. Here's what I found:
Scala is enormously versatile and powerful; Scala lets you define types with great precision and it allows you to define DSLs that are terse and clean. Scala has a lot of cool constructs that one wishes Java had, including a bunch of functional extensions. But when it came right down to it, I ended up coding imperative Java in the Scala language because the complexity of all that cool stuff overwhelmed me.
I did some Lisp back in University, and always had a hankering to get back to it again. Some really cool cutting-edge stuff is done by very smart people in Lisp, and in very few lines. I wanted to be one of those smart people, or at least try to be like them. But I never really understood Scheme, and I missed my "infinite supply of libraries" from Java. I couldn't see myself writing a GUI in Scheme, and had trouble envisioning a Web application.
Then I tried Clojure and it seemed like everything clicked into place. Clojure was intentionally made more outsider-friendly: There is an attempt to cut down on the parentheses and to use different parenthetical punctuation for different situations. Treating things like arrays, text and XML as sequences, combined with a powerful set of sequence functions, made a lot of problems quite simple, as does the support for arrays and hashmaps. It's (intentionally) like functional Java. The functional mindeset takes a bit of getting used to, but nowhere did I find it as approachable or as enjoyable as in Clojure. My code hardly needs loops any more, yet it's more clear about where it's looping/sequencing, and more concise. I can do mutable state if I really need to, but I have to be explicit about it; in exchange, that state is protected by Clojure's concurrency mechanisms. Concurrency, then, becomes almost a no-brainer, sometimes my code executes safely in parallel with no conscious effort of my own.
Not coming from Java, this will not seem very useful to you, but Clojure can do anything that Java can, including fully compatible .class files. Most importantly, it can interface with all Java libraries, and that ability alone will make PHP seem like a toy language to you.