Gmail is wonderful. It gives you around 1GB of storage space for no-spam email. It can give you even more.
How I use it:
Why?
I love having all messages stored. And I have everything stored on my main machine. But, since Gmail has 1GB of fast-search-capable storage I prefer browsing through my mail using remote Gmail than my local Outlook. Implicitly I get web access to all my email.
We're probably more that three years away from achieving this on our local machines.