I will vouch for judo. It is good for self defence and an olympic sport. It's nice to be able to end a physical situation without throwing a strike...generally people will back down once they get tossed once. If you do research ontario has some very well run, legitimate dojo's. I don't see how you could go wrong with greco wrestling either. I haven't done it since I was 18, but the basics are still there...kinda like riding a bike.
That being said i have a groupon around here for muay thai classes that I should use soon...that might be fun as well.