I've not yet met anyone who hasn't enjoyed Fantasea!
Its a sort of Vegas show based on Thai culture, don't want to give too much away, but have been three times now, and the show doesn't change but i liked it each time.
Tips: Don't bother with the meal offered its overpriced and a bit like the feeding of the 5000.
Upgrade to a VIP ticket, you will be really close to the elephants.
You can't take cameras into the theatre but worth taking as you can use on the site and good pics to be had.