Just a question: Will this review include the major webmail clients such as Gmail and Yahoo? I mention these two because at 2+Gb, they're essentially unlimited email. I know Gmail does almost all of what Jibz listed above, but its filtering capabilities are almost unmatched. I'm not sure what percentage of people have a webmail account on top of their POP3 account, but when I travel, I don't have to worry what is where (or what is left behind on the home system), I just use Gmail and be done.
I'm different because in the past, most of my email time was wasted time. It's not much different now except I answer it 2-4 times a MONTH.