For my information, can you explain what you consider good about threads?

My overall opinion is still pretty much what I said a long time ago at Threads vs Forking (Java vs Perl). Switching threads is faster, debugging multi-threaded programs is much harder, and as the tangential discussion at the end points out, forking scales better if extreme scalability is needed. (The fact that high-end boxes now tend to jump hoops to avoid scheduling different threads on different CPUs underscores the fundamental scalability issue.)

I have updated some parts of my opinion though. Perl 5.8's threading model makes threading usable in Perl for definitions of usable that include slow and memory bloated.

Therefore I would personally avoid going multi-threaded unless I was writing code to run on a platform that strongly pushes you that way (Java and Windows both come to mind), or unless I was writing an application where interactive latency was significantly more important than throughput (eg a user-facing desktop program).

However I haven't done much with threading (the above shows why I tend to choose not to) and I like to update my information from time to time. (And yes, I do regularly wind up changing my opinion as well...) So I wouldn't mind feedback on why you think that threads are the right direction for people to take in more situations.