I guess this won't really be much of a thread, but I just found this out off the apple website and it helped me. I've been having trouble using 'capture now' in FCP4 since I upgraded. It kept crashing on me and causing a whole lot of trouble. Turns out norton antivirus is the cause, so you need to turn it off when using capture now.
In a desperate attempt not to make this a single post thread that will jsut sit there annoying the hell out of everyone until it moves far enough down the list where no one will ever see it again, does anyone know of any other glitches that we might be interested in solving on our own systems?