I'm glad I'm not the only one who has 2 or 6 or 12 back up machines. My best purchase was a treadle, because whether there's electricity or not, I can still sew. I purchased those LED lamps that have the solar battery charger, too. After living through Hurricane Ike (and no electricity for 5 days), I was so glad I had the treadle and the lamps.
Also, I believe that everyone should have one mechanical machine. The Singer Featherweights are great. It only has a straight stitch, but it's a workhorse and once you get familiar with the machine, most problems can be solved by yourself.