I haven't had any problems for quite a while - knock on wood!
I have Verizon e-mail, (well, I use Outlook Express, but my address ends in verizon.net), and after reading the above posts, I sent myself a test e-mail about 1/2 hour ago. Just heard the little "ding-dong", checked messages, and there are 5 new ones, including the one I sent myself. So apparently it's working here.
I guess my squirrels are behaving themselves......

Or does Outlook Express have anything to do with it?