I could go into lost of details, but i'll try to keep this short. (not that it;s brief).
1) if you drive an average 250mi/wk (12K per year), a common hybrid or micro diesel pushes that on about 5 gallons (US) of gas, or about $18-20US per week. The leaf uses 30-32KWh to charge from dead empty (but it never really can be now can it) and given the last 10% of the charge is hardest, you'll get about 33-35KHw average per 100 mile equiv charge, so ~100Kwh/week, ballpark US at $0.10/kwh = ~ $10/week, or about half the price of gas in a comparable small hybrid car assuming a 12K mile annual driving habbit. Because of summer and winter (mostly winter) inefficiencies, you can reliably trust the car only 70-80 miles a day unless you can charge while at work so keep that in mind.
2) CO2. Pretty much the simple answer is, unless more than 50% of your power comes from renewable sources, it is NOT greener. Wells to wheels figures put oil at about 23lbs CO2 per gallon (19lbs is from burning it, the rest refining, mining, transport is a small part of the total). Coal is 2.1lbs/kwh just burned. Mining, storage, and transport is actually WORSE than oil (oil is mostly pipe-lined, coal has to be manually moved in fuel burning vehicles, and drilling vs mining, mining is also worse). Natural Gas makes 1.9lbs CO2/kwh. 56% power from coal, 20% from natural gas, just combustion, you;re at about 1.5lbs/kwh. 150lbs a week, give or take your region. This does NOT include transmission losses (but the roughly 33KWh figure /100 miles above does), and does not including mining/refining. 5 gallons of gas = 100lbs CO2 (+ mining refining) and electricity = 150 (plus mining and transport). That's just CO2... Sulfur, Mercury, and other hazardous EPA managed output from fossil fuel electric generation is about 3-6 TIMES as high in an EV than burning even diesel fuel.
The environmental impact of an EV is much heavier than a standard car. By some estimates, building a car is half or more of all of its CO2 output it will ever have. I don't know if I buy it, but an EV is more impact as making those batteries, and the rare earths in the motors is higher than the impact of a block of iron for an ICE. By how much? VERY hard to tell.
A comparable micro-diesel, with similar interior room, and driving performance, is about $7-15K less than an EV (depending on subsidy, and considdering some microdiesels and hybrids get their own subsidies too). Odds are, at even twice the driving range (pushing an EV to it;s theoretical max per week given charging times), gas prices have to go over $6 within your first 3 years of ownership, and continue to rise to $8/gallon inside 7 years, while energy prices stay the same (unlikely), in order to break even. This does not take into account higher insurance on EVs, and higher repair bills, nor that battery swap every 10 years... They will also likely depreciate in value VERY fast as newer battery tech and better systems are coming out rapidly (current EVs will be obsolete in 5-7 years, replaced by MUCH better ones, and battery prices are falling by as much as 25% a year. buying an EV for economic reasons is not sound. buying an EV for environmental reasons is not sound (unless you live where more than 50% of power is from solar/wind/water).
There's a lot of fuzzy math, and a lot of FUD out there. One thing to keep in mind, that EV, it uses as much as half a common house in power every month (or more) per car. We can afford a 1-2% increase in total grid output in the USA right now, and power capacity is not expected to dramatically improve for 5-10 years. That means 1 in 75 houses can have an EV, and even this is limited to areas not already strained by underdeveloped power (California, southeast USA, etc).
They ARE the future, but we're not in the future yet. EV development has to continue, and to do that they need SOME of the cars to sell, a small number, governmet subsidized. In 20 years we might be able to start selling them in masse, but for now only confused greens and misled people believe they're doing something good by buying one (other than supporting a growing economy).