Cool, it looks like I'm in very good company with my position on threading - Mark Roseman singles out exactly my point:

"Now that the best and the brightest have spent a decade building and debugging threading frameworks in Java and .NET, it’s increasingly starting to look like threading is a bad idea; don’t go there. I’ve personally changed my formerly-pro-threading position on this 180º since joining Sun four years ago."

See Tim Bray's weblog for more.

Update: more good company - Donald Knuth has this to say:

I won’t be surprised at all if the whole multithreading idea turns out to be a flop, [...]

and about multicore:

How many programmers do you know who are enthusiastic about these promised machines of the future? I hear almost nothing but grief from software people, [...]

Read the interview for context.