I couldn't go back to POP3 now. It's an IMAP, or it's nothing.
See, I have POP3. I've tried IMAP, and I just can't get to like it. I hate it.
Also, for the poll, Gmail FTW!
Besides Gmail, however, I have pretty much as many emails as you can think of. At least 4 gmail accounts, 3 hotmail, 2 yahoo, an undergrad college one, law school one, comcast one, you name it. And with the exception of the hotmail and yahoo accounts (b/c they don't play well with Mail.app when POP3), I have like 8 accounts set up through Mail.app. I love it!
P.S. And for those who are wondering, yes, I do use each and every single address for different things
🙂 (i.e. undergrad communication, law school communication, one for eBay account, one for spam account, one for craigslist account (totally annonymous), etc.)