Currently I use a Yahoo! email address as my primary email address. I also acquired a Google Gmail account since I'm a user of Blogger(email@example.com). Now, the big attraction of Google is that they give you a massive storage capacity. One gigabyte in fact. Way too much for any normal user, in my opinion.
However, this overwhelming competition from a highly respected company such as Google has been good for the email service industry, because now Yahoo! and Microsoft's Hotmail have upped their storage capacities for their email services. I know that for Yahoo you get 100MB. And if you choose to pay for their email service, they'll upgrade you to 2GB, twice as much as you get with Gmail!
But who really needs all that? Email is not a good way to transfer files in general as it is inefficient. So 100MB seems just fine for me, and they even upgraded their interface to at least look more like Gmail's. But it's really just the same, and not an innovative evolution like Gmail. Gmail's interface makes email more like an IM conversation in which you view emails between you and another person in chronological order. Very intuitive and efficient.
I have a complaint about each, though. Since Yahoo upgraded their interface, the email preview feature on the My Yahoo service doesn't seem to work. I hope they get that fixed soon, because it's annoying to have to go to the mail site manually. My complaint about Gmail is that it doesn't yet support the Opera Web Browser, which I use. So at work I downloaded Mozilla Firefox so I can use Gmail without having to resort to good old IE :-P That contributes to me sticking with Yahoo for now, until Google implements support for non-ActiveX browsers.
So that's my take on the current email situation. Hope it helps!