Rainer Joswig has a nice video up demonstrating how to debug Lisp with Slime. In a sense there’s nothing new here: most Slime users are pretty much aware of the facilities that he uses. Nevertheless, it’s very useful to see someone put them to use on a real problem.
Joswig makes the point that the Emacs/Slime combination is equal to any dedicated Lisp IDE. Not being an IDE user, I can’t verify that from personal experience but I do know for sure that I don’t want to deal with more than one editor. If the only thing you do is program Lisp then by all means use an IDE if it meets your needs. But if you’re like me and use your editor for darn near everything and if, also like me, you are easily confused by multiple editor interfaces, then stick with Emacs and Slime and be happy.
The video is a bit over 15 minutes so it’s easy to fit into a coffee or lunch break. If you use Lisp and Slime this is definitely worth a few minutes of your time.