I have my Gmail, Hotmail and Virgin email addresses all fed in to my Thunderbird, allows me to deal with the 3 of them quickly and efficiently. I hardly ever use my yahoo so I keep that just for when I have to sign in there and check quickly.

At work we use Outlook all the time. I'm well versed in both thunderbird and outlook. Though I've noticed many offices these days using emails with the gmail interface. Good job I'm fair whiz at that too.