This mostly-web programmer finds strace and (more often) ngrep (http://linux.die.net/man/8/ngrep) to be some of the most useful tools out there for debugging errors both strange and mundane.
For me as a user, strace can be a real life saver. I'm not hep enough to the jive to read the source code and figure out what [incredibly uninformative error message regarding file access] means, but I can read strace output and see what file the executable is trying to access, and what it's trying to do to it.
My favorite strace story: trying to get at the underlying causes of some "Unexpected Error" messages in ArcGIS, and it turns out it's writing helpful and useful (albeit two decades old) logging + error messages to the Windows equivalent of /dev/null.
Yes most definitely, strace / truss have been absolute life savers. And if you are looking for something similar on Windows Process Monitor is excellent. You can also do a lot of DTrace style stuff with WMI and VBScript.
A cute goth daughter of a friend once squealed with delight when she saw another friend of mine (a NASA hacker) type 'monkey' into Terminal.app and cause some remote login magic to happen.
Oh, the arcane magic of "alias." Then again, there have been times I've seen young people impressed by what amounts to "Row, your boat" played on an actual mandolin.
To be fair, many of us web programmers use the command line extensively. 75% of what I do is web work, and It's all written in vim, and often ssh-d into a server. I got my irssi running in a tmux session 24/7...
Web programming has much more in line with systems work than most appreciate.
