From The Register, UK:
Get a TDi estate not an EV, and save the planet! By Lewis Page, 8/31/10
Swiss boffins have mounted an investigation into the largely unknown environmental burdens of electric cars using lithium-ion batteries, and say that the manufacturing and disposal of batteries presents no insurmountable barriers to electric motoring. However, their analysis reveals that modern diesel cars are actually better for the environment than battery ones.
The revelations come in a new report  issued by Swiss government research lab EMPA, titled Contribution of Li-Ion Batteries to the Environmental Impact of Electric Vehicles. The Swiss boffins, having done some major research into the environmental burdens of making and disposing of li-ion batteries - to add to the established bodies of work on existing cars - say that battery manufacture and disposal aren't that big a deal. However, in today's world, with electricity often made by burning coal or gas, a battery car is still a noticeable eco burden:
The main finding of this study is that the impact of a Li-ion battery used in [a battery-powered car] for transport service is relatively small. In contrast, it is the operation phase that remains the dominant contributor to the environmental burden caused by transport service as long as the electricity for the [battery car] is not produced by renewable hydropower ...
A break even analysis shows that an [internal combustion engined vehicle] would need to consume less than 3.9 L/100km to cause lower [environmental impacts] than a [battery car] ... Consumptions in this range are achieved by some small and very efficient diesel [cars], for example, from Ford and Volkswagen.
Actually quite a lot of the new diesels are in the better-than-battery ballpark, according to UK government figures. The notional battery car considered by the EMPA analysts was a Volkswagen Golf with its normal drivetrain replaced by a battery one: but it seems that you would be doing slightly better for the environment to buy an ordinary new Golf  with a 1.6 litre "BlueMotion" injected turbodiesel - which would be a lot cheaper. That would consume 3.8 l/100km, not 3.9.
So would a new Mini Cooper D hatchback or a new Ford Focus, actually. And if you could bear to go for something a little smaller - VW Polo  rather than Golf - you'd be streets ahead on the environmental front, down as low as 3.4 l/100km with more than 15 per cent of the car's in-service emissions clipped off compared to the 3.9 l/100km battery-car baseline. As the Swiss boffins tell us, it's the in-service energy use and emissions which count most.
You could even treat yourself to a small estate car - the Skoda Fabia  - and beat a battery Golf by a large margin in terms of eco-credentials, according to the EMPA analysis.
Of course, battery car lovers will argue that's not the point. Swiss electricity is already largely generated by carbon-free nuclear and hydropower plants (carbon-free provided you don't count all the concrete used to build them, that is). These and other technologies not yet much used (solar, wind, tidal etc) may one day put the battery car far ahead of internal-combustion ones in terms of carbon emissions.
And if nobody buys battery cars now, they'll stay expensive and scarce forever, so it's still possible to view the act of buying one as green even today when they actually do more damage to the environment than the right internal-combustion model.
But if you just want to emit less carbon right away, it seems you should buy a modern eco-diesel rather than an electric vehicle.