What you describe is unfortunate, but not suprising. The vast majority of my machine lockups are because of XFree wedging (on i8x0 and radeon, g400 and mga are pretty stable). It is probably the least reliable bit of software that I run regularly.
Spam is evil, especially on when it appears on my mailing lists (which I keep open as a matter of principle). Recently I have started using SpamAssassin as a frontend to Mailman. This worked reasonably well: tag messages in SpamAssassin and get mailman to block anything with "Subject *****SPAM****".openssh:
Unfortunately, mailman doesn't actually block those message - it just queues them for approval. So every month I have to go through the abysmal approval interface (the only part of Mailman I dislike) and click the tiny "discard" button for each of the ~150 spam messages I get every month.
Today, prompted in part by a massive increase in spam over the holidays, I finally had enough. The mailing list server still scans with SpamAssassin, but now automatically bounces all spams (with a useful error) which SpamAssassin has tagged. This was straightforward enough, once I had figured out the many quirks of procmail.
In the process of figuring out procmail's quirks, I looked a couple of times at the source. O Gorgon! There was no way I was letting that mess run unsupervised on untrusted data so I hacked up an OpenBSD systrace policy for it (systrace is very nice).
If anyone who runs mailing lists is suffering from similar problems, I'd be happy to share the glue that holds this all together.
I finally have found some time to do some hacking on OpenSSH over the last week. Much of this has been tidying and merging patches from other people, but has also included a fair bit of hacking on sftp. Much more to do though, but it is nice to be productive again.