I've been remiss about my haunted houses. I haven't been to all that many- I've been far too distracted by making little nothings and setting up my shop and all.
However, IBM SOA Adventure Island has a rather neat maze. The ways to get through it are not always readily apparent, which is totally awesome. I really loved the prim ghosts, they were very nicely done.
I saw the best sculpty skull I've seen yet there- a Light Waves, of course.
It's not all spooktacular, but it's rather well done and pretty (it was filled with butterflies in one grotto when I went, due to an event, which sort of downplayed the spookiness factor).