I will give my vote to rig grease as my long term storage solution. For Lubrication and use in the field I use Breakfree mostly because I have a gallon of it and I likely won't need to buy anything else for a while.

I have had friends recomend birchwood-casey something maybe "sheath"?? any comments on it? The friends who use it seem to think its the best thing for their flinters which seem to require a bit more care than most centerfires.