I realize this is a late post here, but since I was looking to expand out and didn't see it: I really recommend that you look into Primefaces as well. I am still relatively new to JSF (1 year development time) but I've been trying to do each new subset in our research phase with a different suite.
Here's my experience:
Icefaces handles AJAX without much work on your end. When you're trying to do something relatively simple Icefaces does a really great job of a small DOM update and a responsive UI. I highly recommend that someone new starts here as you'll be able to get something working quickly and learn all the ins and outs of JSF without suffering. (It also has decent Eclipse tools)
Richfaces is a good suite, it handles ajax in a finer grain (closer to how JSF2.0 works) The components are a little lacking in my opinion, but if you're customizing the look Richfaces is a better place to start as it generally feels easier to skin. (Then again, plain JSF2.0 works for this).
Recently I tried out Primefaces (http://www.primefaces.org). There's a lot more work involved in this suite as far as can tell it has a significant advantage in the number and look and feel of the components. Of the above, I am enjoying working on complex things in Primefaces that were utterly frustrating in Icefaces.
I hope this helps another reader, I think all these suites are great. If you're doing some insane Javascript and you need fine grain control go with Primefaces.
Another small note: if it is a new application, use JSF2.0--it has significant advantages and I have yet to find anything that's frustrating.