haha, I had a similar question recently, with one pannier and contents being about a kilo heavier than the other. I opted to place the heavier kerb side in the view that if i was going to lose balance weight distribution should determine the way i fall, and id much sooner that be on to the kerb than an oncoming car. Thats my logic anyways!
Non drive cos the upwrong used to be parked that way round at work so it was easy to get the pannier off. Now I have both a pannier and an rack pack - I make do with the rack pack but the pannier still fits non drive on the Orca.
I've heard folk saying right side as it encourages better overtaking and also is less likely to be interfered with by Peds. TBH though I don't bother I think most of the time its on my left as I lock the bike up on the right and its easier for me to access.
On the left though my logic was not that of the above (though that makes sense), it's on the side that the stand is on, and if I need to do any gear-tweaking (possibility of tweaking en-route is ingrained from a youth of bitzas) I don't have a pannier in the way.
I alternate sides, usually depending on which pannier I pull out of the cupboard. I have a preference for having it on the drivers side though as I'm an advocate of the theory it encourages drivers to give a wider berth.