I will choose Play and Scala. Although JRuby/Rails comes as a very, very close second option (simply because all the cool things have a gem, not many have a Play module) But I want to have some sort of static typing to protect me, and as a Java developer, it's where I feel a bit more at home. Clojure is what I'd LIKE to use (with Noir) but I don't have the guts to be honest.

If Play had all the community and gems that RoR has, it would be a very, very strong framework, and something that the enterprise world would (years from now) adopt more likely than RoR (for all the wrong reasons, but such is life)