Well, it looks like there aren't a lot of us. I'll start with a question:
I'm a [mediocre] keyboard player, when I compose, I "hear" my compositions fully orchestrated. For this reason, I find myself working with multiple synths/samplers/VSTs. Though it's gratifying to hear a more-or-less complete work, it's not the fastest way to work. On the other hand, playing with the orchestration up front lets me say more with the music than if I just wrote a piano reduction (which wouldn't be very good -- as I said, I'm only a mediocre keyboard player). Still, with music functioning as an actor, I don't know any other way to do it than by orchestrating as I go.
What does everyone else do?