July 4th, 2007 is a Wednesday. So, which weekend is the "holiday weekend", 6/29 - 7/1 or 7/6 - 7/8?? Online and real-world opinion that I've surveyed is right about 50-50. Kinda makes it hard to plan something when you don't know when exactly the traffic will be bad.
I kind of old and such. I remember when a "holiday" fell on the day it fell on and three day weekends were unheard of. For me July 4th is a celebration of the founding of my country. I also do crazy stuff like attend the Memorial Day service at the cemetary to honor our military. I sympathize with needing time off but does it matter which weekend it is. But to answer your question, the previous Saturday is June 30 so I vote for the wekend after.
It won't be in theaters long, but I loved it. It's wacky fun. If you thought the trailer/commercial looked at all entertaining, you will love the movie. (And, conversely, if the trailer/commercial didn't appeal to you, you can skip this one safely.)