I have a pirate themed haunt, I find it very eay to come up with ideas for that show as opposed to the others. I would say my least favorite theme is the generic victorian manor theme, Its fairly limiting and VERY VERY popular, we have several great shows in my area alone but its almost over done as far as number of attractions or very loosely adhered to because of its limits.
Asylum is a good theme and can make a strong haunt, I also like Castles, I can see a prison theme being limited but providing a high energy show.
For those who are budget minded the Cannibal/zombie redneck theme is cheap and effectve.
At my park I have a Castle, a pirate show (3-D), an asylum, a graveyard, and a death trap maze (light Saw theme) as well as a pumpkin patch.
The trail I own inside the park cycles through 5 themes so it changes each year. they are, Realm of the Beast (gets to vary this year it was werewolves), Maze of the Minotaur (greek myth monsters), Frozen with fear (yeti), Classic creature feature (classic black and white movie monsters, sets and all costumes are in black and white I love this one) and lastly "The Infestation" (bug themed pretty high creep factor there).
so the haunts I work on for SCREAMS are pretty normal but the trail I have alot of fun with.
I guess I love off the wall themes where I am immersed in another world.