In my case I needed to be able to degrade gracefully when Javascript wasn't available, which meant I had to be able to do it server side as well. If you don't have to support that use case its definitely a lot easier.
p.s. If this happens to me, I expect I will extend my experimental Javascript view-controller framework so that it runs inside node.js. That way I could serve exactly the same content whether I was running in the browser or in node and I wouldn't need two sets of view logic.
Yes! I haven't gotten too excited about the whole "run the same code on the server and the client" aspect of Node (mind you I've been very excited about other aspects of it, its my new favorite framework/whatever-it-is), but this is one application where I really think that could be beneficial.
