I have had great sucess with Miltonia's see thread Pics of Semi hydro success with 3 of my Milts in bloom.

Oncidium alliance orchids, such as intergenerics and hybrids are a natural for s/h. I also have great results with Cattleya's, Paphs and Phrags. I have had mixed results with Phals, and tend to grow most of them under traditional culture, but do have a few in s/h and they seem to be doing fine. The key is to convert to s/h when new growth occurs, as assimilation to new culture is much smoother. Otherwise, you have to nurse them along.

Gregg C.