I never made the transition from Doom and Duke Nukem 3D, except adding a mouse (which I did later in Duke3D anyway). I've always played with arrows, WASD has always felt wrong to me, and yep, I'm right handed. I've tried to get into WASD a few times, but using the arrows just seems more comfy and logical, i.e Up is Up, rather than W is Up. That'd be like using the gear stick to steer a car instead of the steering wheel. I think it's comfy too, I have my whole arm rested on the desk, it's nice and relaxing while blowing chunks out of things, and it feels different enough to typing to make the game feel more like gaming.
That's just what I think anyway, each to their own, but the choice should always be given. I know there's other keyboard setups people use too, so that's why it's good to have custom controls.
The only problem I find with using arrow keys, is... that's all you CAN use.
With WASD you also can easily press SHIFT with your pinky finger, space bar with your thumb, and buttons like E and Q for things like "use" or "reload" etc... with arrow keys you are pretty screwed when it comes to using any other buttons...
And unless you have to look at the keys when you press them, then just imagine that the W has an up arrow on it... or buy an optimus maximus keyboard so you can make the buttons look like whatever you want instead.
~Sol