Personally, for the money, I would consider a Prius Plug-in, Focus Hybrid or even a Lexus Hybrid.
The cost of the Volt is high and the $7500 tax is good but not great.
The LEAF is an issue since it is a totally electric car. If you run out of charge you are out of luck. There is also a problem with battery memory and the batteries are not made for high heat or cold. They are basically worthless in northern climates. At 0 degrees Fahrenheit they will lose half of their battery capacity.
If you have to get a Volt or LEAF, I would go with the Volt but it would be a "have to" situation. Hopefully, battery technology will improve in the next few years to make the all electric car more affordable and practical.
BTW: You will save a lot on gas but be prepared to see your electric bill significantly increase. However, your overall cost will be less than a hybrid.