There was a survey on the VI-Control forum and Cubase was the most popular DAW by a large margin. Second Logic and third DP.
Many of the composers on the VI forum tend to be younger, so that might be why DP didn't get more votes, which is still very popular among more veteran composers, but in general Cubase tend to be more common, especially with European composers. DP has lost a lot of ground and Cubase seems to work better with VEP, so I think this tendency will continue.
For recording PT is the undisputed champion, of course.
I think DP is still the best software for film scoring as far as features and workflow goes, but the lack of support for VEP is becoming a deal breaker for me, so I might switch to Cubase.