On the other hand I think something like jQuery would come in very handy if you had to add some things to an already existing application where you can pick and choose what you want and where. It is more light weight to implement and less binding. Think about Java and C++
, I sure do not want to keep track of garbage collection having used Java for so long
One thing that is kind of a concern for me is that with this web 2.0 craze applications are again moving to the client and that has its benefits and disadvantages as well. Yes, you do put all the code in on the server but what happens on the client is not under your control, so as someone supporting and writing this stuff I can see some how some problems may crop up that are hard to troubleshoot. The security aspects of this stuff are also interesting.
My 0.02 cents.