I took a look at Log::Log4Perl, and it looks very cool. I'll take a closer look this week.
I like the idea of logging to syslog and then scanning through the logs, especially if I use a central logging server.
Regarding the eval {} test idea, I actually do worry about every line of code causing my script to die. Or more accurately, the one time I forget the eval {} test is the one time I'm going to really eat my own foot. So, I really need something that logs/emails problems that I don't forsee.
Nagios sounds like something nice for monitoring if your web server is running or something like that, but I really want something that's going to send me email when my account creation script finds a line from the student registrations dump that contains a field it can't parse. Am I missing some features of Nagios that are cooler than I realise?