So now that I've used Gmail for a couple of days, I can say that it is without a doubt the best webmail client I have ever used. It is fast, it has lots of keyboard shortcuts, and it's really designed with the power user in mind. It disables html images by default which is great to prevent stupid web bugs.

That said, it may not be enough for me to switch to using it exclusively. The keyboard shortcuts are great for dealing with lots of junk mail, but so much html email is meant to be used in a browser that you still kind of have to rely on a mouse to navigate.

The spam filtering is not as great as my current solution, but it may just require a bit more training.