I prefer Gmail via web interface. Sometimes Squirrelmail running on my server. To access certain accounts I don't want crapping up my Gmail, I use Mail.app in OS X. I've used Evolution in Linux at times, it's better than most. In college we used Pine, but it wasn't for POP3, it was for IMAP. If I'm in need of a very fast glance at email on a server, I use fetchmail in Linux. At work I'm forced to use Outlook. I stay far away from Thunderbird. I would not wish Outlook Express upon my worst enemy.