Or another possibility: let the Electorates of each state split their votes. E.g. CA has 50 delegates, and 60% of the people vote for the Dems and 40% vote for the Reps. Then 30 Electorates may vote for the Democratic candiate, and 20 delegates may vote for the Republican candidate. This would be more fair for the 40% Republican voters in CA - or for the Democratic voters in TX, etc...
Why would it be in the interest of states to split their votes proportionally if other states don't? The only way such a thing could happen is if a constitutional amendment forced it on all the states.
You start apropriating electoral votes by percentages and you'll confuse hell out of the government school graduates in Arkansas and West Virginia. Nope, appropriation by district will be easier and cause less confusion. Besides, the district where I live has had a democrat congresscritter since, I believe, shortly after Reconstruction (if fact, it's algore's old district) and President Bush carried us about 60%-40% in 2000.