Xbuffy is a program that displays how many unread mails you have in your different mailboxes. You can have different titles for the mailboxes, and define what shall happen when a new mail arrives. It can beep and invoke a shell command, for example.

If you press mouse button 1 on the title associated with a mail box, a list of From: and Subject: lines of the mails in the mail spool file is shown. If you press mouse button 2, an arbitrary command is executed.

Xbuffy can similarly watch newsgroups via NNTP.