Meanwhile, AFAIK everyone has agreed on a standard AC charging connector good for 120/240 V, with the connector itself being good up to about 90A (it looks like Tesla is using it with a 50A rectifier, and Nissan 30A).
Nissan's 80% quick charge in 30 minutes connector probably isn't quite high enough wattage to 80% charge a 53 kWH battery pack (as is found in the Tesla Roadster) in 30 minutes, and I think that 80% in 30 minutes may be the magic cutoff for claiming the $5000 California tax credit for buying one of these things, which leads to the question of whether Tesla will have an incentive to get quick chargers introduced which will be incompatible with the initial version of the Leaf.
(As a practical matter, I think if these chargers max out at 500 VDC at 125A, that's probably good enough for road trips, though higher wattage might be nice.)
Perhaps charging station tech advances the quickest. A business produces commercial chargers and markets them to trendy coffee shops with strip mall parking (that are likely to have "green" customers) or perhaps to non-munincipally owned parking garages in urban areas. And another startup develops and markets commercial chargers for households with garages.
Capitalizing on a decentralization trend (computers in every home) has great business potential. But the venture risk might be too high due and corresponding probability of success too low for this particular paradigm to take hold.
Battery swapping for trucking has the advantage of being a smaller, easier to target market. But the disadvantage of less electric vehicle tech.