Since got the iPhone, I've been using it to access my Gmail account. By default Gmail runs IMAP in iPhone, which is great if one will access the e-mail on multiple computers. The downside, of course, is the heavy usage of GPRS/EDGE (which is kind of slow).
I've been using Gmail's web-interface for quite a year until now - when I found this article:
Turn Thunderbird into the Ultimate Gmail IMAP Client
Let's see how it goes on Thunderbird, compare with the already-familiar web-interface.