You can probably predict what I'm about to recommend:
Thunderbird.
And while you're at it, stop using IE, and switch to Firefox!
Anyway... A long time ago, I used to use Eudora, and liked it. Haven't seen it since 2001 (and Win95), but it's probably still just as good.
I'm stuck with Out-leak in the office... At home I only use web-based email... but the next time I have a POP3 account, I'm going back to T-bird.