I got my Inbox back down under 40 (from about 90) and my mailing list folder to 0 (from 550). Feels good to be getting back in control of things.
My current mail client of choice is actually Thunderbird on PC. I open e-mails in new windows, using the main window just as a display of folders and the list of messages. Thunderbird will open the next message in the list once the current one has been processed; good for slogging though lots of e-mail at once. I just wish I could QuickFile from the open message window.
I’m (sigh) once again back to Mail.app on the Mac and I hate the “drag and drop only to a folder list that jumps around unexpectedly and makes you drop it in the wrong place half the time” filing process.