dwmw2
mentioned that he can't live without a tree view of mail folders showing which have new messages.
I currently use a combination of procmail, mutt, and my own scripts to sort and read mail. The procmail script sorts the mail into organized mbox files in ~/Mail/. Then I run newmail to get a list of mailboxes with new messages in them. Then I use
mutt -f Mail/mboxfile
to read.
Here's an example of my "newmail" output:
Total New Mbox
------ ------ ----------------------------------------------
55 1 barry
158 21 *bochs-dev (1)
2096 1405 boost
446 444 *bugtraq (3)
80 78 bugtraq-generic
402 144 c++
4072 3 canada-dmca-opponents
1200 157 *cdfrey (1)
166 120 debian
246 67 gentoo-announce
41 15 *gentoo-desktop (1)
1848 1022 gentoo-dev
38 6 gentoo-gwn
82 28 gentoo-hardened
355 237 *gentoo-portage-dev (1)
605 62 gentoo-security
276 247 *gentoo-server (4)
1217 1217 git
11 10 gnupg-announce
91 90 gnupg-devel
423 331 gnupg-users
129 82 kt
1162 8 kwlug
364 133 libusb
10023 10022 linux-kernel
601 344 linux-thinkpad
144 144 *mailer-daemon (5)
551 314 mplayer-users
411 401 open-graphics
1404 164 plusplus
541 35 plusplus-commits
63 34 risks
211 189 slashdot
47 2 spca50x-devs
8 1 xboard
Yes, I'm a little behind. :-) This shows the total messages in the mbox file, the total unread messages, which mboxes have had new mail since I last checked (*), and how many new messages arrived since I last checked.
It's worked pretty well, not only as a mail system but as a spam whitelist too. I only use the code personally, so the code isn't polished for release. It's a single .cc file that can be compiled standalone, so it shouldn't be too hard to play with if you want.