[citation][nom]rebturtle[/nom]So will lefties re-map all of their keys? W-A-S-D --> I-J-K-L?[/citation]
Already do. I've been using Razer mice since the very beginning, with the Razer Boomslang. Thankfully most of their mice are ambidextrous, but I am happy to see them building an ergo model specifically for lefties. I will stick with my ambidextrous Lachesis.
And yes, I move with I,J,K and L. It does require me to re-map keys for just about every game, but the benefits are vast. With W,A,S,D, the only keys you have to the left of those keys (and thus easily accessed by your pinky or ring finger) are Tab, Caps Lock and Shift. With I,J,K,L, I have gobs of keys to both the right and the left of my movement keys for me to choose from. Some of my most used keys are all the punctuation keys (7 of them on my keyboard), right-shift, and return to the right of I,J,K,L, all of which can be reached with my pinky while not lifting the rest of my fingers from my movement keys.
Frankly even if I did play right-handed, I would still re-map closer to the center of the keyboard in order to have more available keys for my pinky finger. It makes a big difference.
Another benefit of mousing left-handed is that since the number pad is on the right side of a full-size keyboard, you can have both your letter keys and your mouse closer to the center of the desk. Think about it. Right-handed, if you center your letters on your desk, the number pad pushes your mouse way out to the right, or you end up shifting your keyboard off to the left. So unnatural.