Here are my numbers:
I own 3 vehicles, a 2013 Leaf, a 2004 Honda Pilot, and a '91 Dodge Dakota pickup.
I record all my fuel costs. Just finished my 3rd quarter fuel cost analysis.
March 12 thru Oct 12 2012 (pre-Leaf, gasoline only): $3,690
Same period this year, post-Leaf: $351 (gasoline only)
Net fuel savings = $3,339 - $142 = $3,197
Leaf miles as of today =8,012
Avg miles per kilowatt hour = 4.5
Total kilowatt hours consumed plus line losses = 1940 KWh
Electricity here costs $.073/kWh
Total Leaf power cost = $141.62 for 8,012 miles
That's about 1.8 cents per mile for "fuel".
Now factor in the cost of the Leaf. Lease pmt + lease costs is $416/month times 9 months = $3,744
So, all things considered, I come out just about even. But I get to drive a new, excellent car every day, pretty much for free. Now I have 10kw solar panels, so I don't even pay for "juice" now.
Bottom line, as all other posters point out, cost of electricity is insignificant in all of this.