Running a Quad-Core 2.66 Mac with 10.5.8 we got new in November of 2009. I use FCP 7.0.2, After Effects 7, Photoshop CS2 & AJA Kona KHi-RO card.
The keyboard stops working for short periods of time before suddenly kicking in again. It's not a delayed response either; i.e., it doesn't store everything I'm typing and then suddenly all the characters appear once the keyboard is working again. It just completely stops working and I have to retype. It happens with all programs I use and all keyboard functions, including shortcuts. This has been going on for a while.