I was there from the 18th to 25th in 2003 and it was pretty dead. The beginning of the days at the parks there were maybe 20-30 min waits for major rides and attractions but by like 3 o'clock you could basically just walk on rides. I remember waiting just a few minutes to get on Test Track and there are always long lines for that. If you are going to Universal, it is really dead there. I really felt I had the whole park to myself there. I hope this helps. I'm going the first week in Oct. this year so hopefully it will be quiet there at that time.
Jeff