It sounds more like you want to learn a web framework than a new language. Picking a framework depends on what your goals are - do you want to develop REST based services, write rich-internet-applications, or do more traditional web-apps?

Cappuccino looks interesting for developing RIAs (or whatever the current buzz-word for these things is) but I wouldn't use it if you're just looking to develop the next best blog engine. Same for Google Web Toolkit (GWT).

Django, Rails, and the like seem to be a good fit for a wide variety of things - blog engines to photo albums and on.

Now, if you really do want to learn a new language, try taking a look at Erlang. My background is similar to yours and I started looking at Erlang recently and have really enjoyed it. Combine that with the Nitrogen web-framework and you've got a really powerful and fun combo. Now, you won't be able to deploy it on your shared host, most likely, but it's not difficult to set it up on a cheap server in the Rackspace Cloud (or elsewhere).