As for a free email provider.....maybe more space. Yahoo accounts are too small.

Strong spam filter. I have accounts with myrealbox.com and they do an excellent job on spam. My other free email accounts are very poor on spam.

No Advertising gimmicks. I don't have a problem with flashing banners. I do have a problem when I have to look at a page before I can access my mail.

Excellent virus protection would be a great feature.