I was reading IT magazine (October issue) and found that Indiatimes has got AJAX based interface for their email. I have an account at indiatimes but had just forgot it (I never check emails because of that world's oldest interface!!) But I opened it now and its cool now. You can drag and drop mails to folders, there are right click menus (GUI is not very good still but hope they will improve it!!)
If you have indiatimes account, go ahead and check it out.. (http://in.indiatimes.com)
Stay tuned..