Dana and worm are correct. The batteries are not the same as what runs your laptop, though the generic lithium-ion describes the chemistry of both types.They are more recyclable and should have a much longer lifespan than current batteries. The new Chevy Volt is going to use batteries even more advanced with nano-materials to keep them working and from leaking hazardous chemicals even if they're damaged.
Saying the battery replacement is akin to replacing your car's engine is like saying you should always get a new flashlight because the batteries died. Who does that unless it's a penlight? Ideally, the batteries will eventually be on a servicable bank that can be swapped out for a fresh set of batteries at a service station, in the same time it takes to fill your gas tank now. They'd then check the batteries and can replace individual cells in that bank and the cost of "refueling" would still be a tiny fraction of what you pay now for gas.
Hydrogen-powered cars are a pipe dream since the main method of making the gas is electrolysis of water and it takes a lot more energy to make the hydrogen than you can get back by burning it or using it in a fuel cell. In the case of the Honda FCX, they make hydrogen from natural gas and the result is a lot more greenhouse gas emissions that you'd get from a similar amount of gasoline.
The best thing would be for the US government to get behind electric power and push for new power plants to turn sun and wind into energy, and new batteries so we can better use that energy in our homes, cars and businesses. That's a far better investment than any carbon-trading plan to reduce CO2 emissions and it could work in a very short time. Germany gets a lot of power from solar because they subsidize it for all citizens. We could do the same here to boost sales of home generating equipment for solar and wind and batteries to store that power.
The main disadvantage of the Tesla is the price, and that will be true of any car in such small production numbers. If they made 100,000 or more a year, the cost would drop very quickly. No heavy engine to haul around, no heavy tank of flammable gas to haul around, there are few downsides to an electric car and a lot of positives.
**Edit** Personally, I'd wait. The next president and congress may implement sizable tax credits or other type of subsidy for this, and the prices will only go down as production of these cars increases. As Dana posted, 2010 seems like a reasonable target date, by then the new battery technologies will be available and they may be making enough of these per month for 'mass manufacturing' pricing to take effect. Sooner if they give you a nice tax credit for switching, but I never count on any politician doing the rational, let alone the best, thing.