If you are still using Yahoo Mail, or just can't get a Gmail invite, Yahoo finally pushed the new version live - with 100MB of storage per account:
It's still not as good as Google's 1000MB GMail, but it's just a wee bit better than the 6MB you got before. ;) (It's also being slow as $##$^@$^ this morning. Yay.)
In other news, Hotmail still gives you a whopping 2MB of space. *cough* Go Microsoft!