This has always interested me. I put the fork in my right hand and the knife in my left, which I know is not the 'proper' way of doing things. But it just feels so unnatural to use them the way you're meant to. My theory is that if I am right-handed (which I am), my right hand is clearly my dominant/stronger hand. I then ask myself which of the implements in question require the most power, movement and accuracy. The answer is the fork, hence I use my right hand for it.
I also do this, but i am left handed in most things, cricket, golf, but i write right handed, i am left footed for football, but feel stronger on my right side, maybe i am just weird