Make sure you're there for the absolute end of the show, when they start to break everything down. There's usually spots to watch from the Hotel, and you can get drinks. What's so fun? As soon as the show ends, workers start removing the docks and all the boats beat feet out of there. It's quite a dance - pieces of docks getting pushed this way, boats under power going that way, boats under sail weaving in between, and a crowd of cheering sailors praising the good seamanship and razzing the bad. Last time I did it I was treated to watching one of the J boats peel away, set an asymmetrical chute, and go ripping through the traffic. So, my advice, go two days - one to see everything you want to see. Then go the last day, when the merchants are having a fire sale, and stick around for the break-down.
Cheap hint - if you're looking for new bullet blocks (like for your jib sheets and such), the Harken booth has "keychains" for sale on the check out counter. They're bullet blocks with a key ring, and they sell for cheaper than the blocks themselves, but they're the real McCoy. Always good to have a few of these in the tool box. At least they did this last time...