I like the two lock method, too. I've used that method with success.
I went a different route recently, tho. I have a really great Bike Friday that I adore, but am worried it will get stolen when I run errands because it's so unique and different. I went on Craigslist and bought a junker Schwinn World Tourist for $20. It's old, it's paint is ugly and rusted and I put stickers all over it. I use that for the grocery store (when I'm inside for a long time) and for when it's raining/wet (when I don't care if it gets dirty). I still ride my nice bikes for long rides, but the "grandma" bike is for those times when I am running errands and am "worried" something might happen to it.
Maybe you could do that? Save the really nice Electra for rides when it doesn't have to be locked up or left unattended for long periods of time.