Glad to hear I'm not alone.
I definitely have a fear of heights, or more specifically, falling from heights. Like Snowolf, I'm fine in airplanes (though unlike him, I'm not a pilot)
or anything enclosed, but open balconies, edges of cliffs, or even floor-to-ceiling windows make me extremely uneasy.
With snowboarding, it has held me back on jumps. I have yet to clear the knuckle on a 20 footer, while my son who started riding at the same time first did it two seasons ago. When I first started, I also had to avoid looking too far down the mountain or I'd freeze up and almost get vertigo. Chairlifts used to make me uneasy, though experience has gotten me comfortable since.
On the other hand, I have been to the top of a couple sailboat masts, which I'm fine with as long as I'm securely in a climbing harness. I'm also fine with jumping off cliffs into water, though I haven't done any huge ones. I guess my fear of heights really is only related to accidental falling.