I would support a system based on proportion of statewide popular vote (i.e. if you live in a state with 10 EV's, you get 1 EV for each 10% of the vote you get, rounding to the nearest multiple of 10%), simply because there are many states (PA, IL, OR, WA, etc.) where non-urban areas typically don't matter in terms of deciding who gets a state's EV's because of the domination of a big urban area (Philadelphia/Allegheny County, Cook County, Portland, Seattle/King County) . Just because you live in a rural area doesn't mean you don't deserve representation in the electoral college. With the current system, you have a situation where (for instance) Washington State's electors are essentially representing the interests of King County, while the rest of the state gets no representation whatsoever, and that just doesn't seem right. (For what it's worth, under this system, Obama would have won 276-261 in 2012, with 1 EV for Gary Johnson in CA. Obama would have 51.3% of the EV's to Romney's 48.5%, for a 2.8% Obama EC margin, which is pretty close to his 3.9% margin in the NPV.)
However, a system like Nebraska's is not something I support, as it would only make the problem worse. Democratic governments gerrymander districts for democrats, and republican governments do the same for republicans, so you'd essentially be leaving the EC open to the gerrymandering that has already plagued the U.S. house. This goes far beyond simply giving rural areas represenation, and instead actually skews the results so that it misrepresents the interests of the nation as a whole and has a much higher risk than the current EC of electing someone who lost the NPV (If NE's system was used nationwide, Romney would have won 274-264 in 2012's EC. This comes out to 50.9% of the EV's going for Romney to 49.1% for Obama, or a 1.8% Romney EC margin, which is off, quite significantly, from Romney's 3.9% loss in the NPV.)
I like this system overall, as it would give red/blue areas of blue/red states proper representation. Someone recently did an analysis on that method. The downside is that it is almost assured to send anything within a 2% PV margin to Congress due to small 3rd parties. However, there is nothing wrong with a city deciding the outcome for a state if the majority of the people in the state live in that city! Having Chicago or Philadelphia or Seattle carry a state is no affront to democracy. Giving Wyoming and Vermont the same number of senators as California and Texas (and therefore exrtra EV) is.
