Rear main seal question

I just picked up a 92 jimmy 4x for almost nothing due to the 3/4 clutch pack being out. While the tranny is out I wanted to change out the rear main. Anyone one have any recommendations on a seal? I have seen rubber and teflon, and a few assorted brands. I am not planning on keeping the truck forever, just a year or 2, but still don't want junk going back in it. There doesn't seem to be much leaking from the seal, much less then I would have thought. I still think I should change the seal since the trannys out.