The absolute best value in Nikon AF film cameras today, for someone who owns only a DSLR, is the F100. Simple to use, great durability, and uses AA batteries, BUT, you can save yourself a ton of loot and just buy a battery pack to use AA batteries with the Nikon N80. I have 2 or 3 N80's and they're marvelous machines. Light, flexible, CHEAP, works with AF, G, VR lenses, etc. I don't see the point in going goofy on any "when I can't get film, or batteries" preventative strategies. Waste of time. Film's not going away. Neither are batteries. You'll likely experience mechanical or electronic failure before one of these doomsday events happens. So buy a 10 dollar backup from eBay and go on shooting.

Now slide film, on the other hand...