As a fellow lefty, I think it comes down to what works for you. You're the one diving your equipment if you are fumbling around trying to operate stuff it is you that pays the price. For the most part, I've had no problem adjusting to the right-handed divers world.. The only issue I've ever had is with my canister light. It just doesn't feel "right" in my left hand for whatever reason and it can be a little clumsy because I refuse to wear my dive computer on my right hand.
If you do end up diving a "weird" configuration, just make sure the people you are diving with know, especially if they are inexperienced, etc. (most experienced people will be able to figure out where things are depending on the complexity of your rig)