Threads are cool. You can do a lot of things at the same time: you can calcuate a response, paint a screen, or even block a resource so that all other threads have to wait -- and all at the same time ...

Seriously, a well threaded application should in these days be the norm. At least that's my point of view, and therefore it is not hard for me to point you to Sun's recent CoolThreads technology (formerly codenamed "Niagra"). The hardware folks put 8 cores on a single die, each being able to run 4 threads at the same time. That's threading - in hardware.