Doesn't it depend on your goals? For example, I expect Haskell to be a hotbed for experimentation for a long time to come. In fact I think people choose Haskell because it is continuously evolving.
I know that I picked Clojure recently not just because of it's features - I picked it because it _wasn't_ stable, it _wasn't_ all figured out. In fact, as part of the community, you can actually contribute a hand to it's future.
It's just Python has matured to the point where people would rather experiment with it's implementation rather than it's syntax/expressivity. It also has to do with the fact that this looks like part of a growing effort to make Python _immensely_ popular - going head to head with the likes of C++/Java.
As far as I'm concerned that's a good thing for Python.
But it does mean if you're looking for new ideas in PLs you'll have to look elsewhere. But it's not like there's a lack of excellent and popular candidates these days.
I find Scheme quite a bit more ugly than Common Lisp. The simplistic design makes it much more unpleasant to use as CL. For learning programming its fine, smaller programming task are fine too, but anything interesting is just a pain. Scheme then provides much on top with SRFIs (and similar extensions) - unfortunately the base language does not scale.
(And I would not want to do loop in Scheme. That's just too imperative. Interestingly Haskell's special syntax for Monads and its lazyness makes the need for most macros / special forms go away (though not for all, and Haskell has plenty of syntax on the surface).)
Consider that Paul Graham, the author of the fine book "On Lisp", chose PLT Scheme to implement Arc on top.
