I'm extremely left-dominant. The only thing I use my right hand to do is throw things (like in bowling or baseball). Other than that I'm left-handed all the way.
About a month ago I switched my computer mouse controls so that I can use it left-handed. Lo and behold, after just a couple of weeks I was as good with that as with my right hand. Funny.
Incidentally, if you haven't already definitely check out handedness.org, which has a host of information about issues facing non-righties. Thanks to it I'm finally starting to correct my horrible, horrible hook writing grip.
Just be careful about the results of your poll; since this is far from being a random sample the results aren't really going to tell you anything about the population as a whole. It'll just tell you the handedness of Escapist users who chose to look at this thread and chose to answer the poll.