Annapolis is far and away the best sailboat show in the US. Don't worry about which day. One day isn't going to feel like enough.
Ft. Lauderdale is huge but is almost entirely power. If you need a boat that comes with a helicopter this is the show for you. I went last year and there were about 10 cats stuck way down the dock
. Even fewer monohulls.
Miami is also mostly power but has some sailboats especially cats. Fewer sailboats each year but the fuel
prices may bring some back. If you live where it's cold, the weather
makes it worth the trip even if you are only looking for a new a teak
cleaner and to chat with the attractive young ladies working at the powerboat exhibits. (this isn't a negative comment against women working at the sailboat exhibits, for all I know they are even more attractive but I only remember the sailboats.)
As mentioned, the last three hours of Miami is a great time to buy equipment
. It's the last big show of the year. The discount goes up with the weight of the item (but you have to figure out a way to lug it off)