Jeff likes this comparison of Background compilation to background spell checking(Background Compilation and Background Spell Checking).
Perhaps the my issue is not with the concept of background compilation but its current implementation. Background compilation is some what slow process on my machines. If I trigger it, I will be forced to wait 15-20 seconds before I can do any thing in that IDE.
I remember a time when the red squiggly first appeared in Word and I turned it off because it was to slow. Unlike Jeff and Ian my spelling and grammar are atrocious. back ground spell check is now at the point where it really is seamless. And a great benefit to my written communication. I find its most beneficial feature is that it offers practical suggestions to my mistake as apposed to just flagging the word. Grammar check on the other hand, well we just don't get along