If you have someone offer you upwards of $12k for the domain, I would seriously consider his/her offer. I don't see a whole lot of development potential with the domain even though it is a rare one.
It could also have potential for any British car fans out there as it is a model of the British car company Rover. Obviously not a big deal though as these are an old model now.
Intel aside, your domain will increase in value everyday. It's like a superb painting by a now dead artist...collectors will be begging you for it. If you're not already comfortably retired, hang on to it for a while and have a bundle of dough for the days on the putting green.
I highly recommend you to wait until(if) Intel releases Pentium 6, then it will be worth much more. I say, if you are in no need of money at the moment hold on to it for a couple of years.