The Clinton campaign claims that since it won the "big states", it makes her a more effective general election candidate. Let's take a look at that logic.
The 10 biggest states by population. I've added numbers form SUSA's 50-state poll matching up Obama and Clinton to McCain.
1.) California: O +9, C +10
2.) Texas: O -1, O -7
3.) New York: O +14, C +18
4.) Florida: O -2, C +9
5.) Illinois: O +29, C +11
6.) Pennsylvania: O -5, C +1
7.) Ohio: O +10, C +10
8.) Michigan: O +1, C-even
9.) Georgia: O -13, C -21
10.) North Carolina: O -2, C -8
Of those, California, New York, and Ohio (all of which Clinton won) are solidly Democratic. California and New York will certainly stay (D) in November. Illinois, which Obama won, is solidly (D) no matter who the nominee is. The two are essentially even in Michigan, while neither is currently competitive in Georgia.
Of the states that will be competitive, Obama has clear advantages in Texas and North Carolina, while Clinton has clear advantages in Pennsylvania and Florida. In the electoral math, that is 49 EVs for Obama, 48 for Clinton.
Yup, Obama has a one electoral vote advantage from the top 10 "big states" that Clinton can't stop yammering about.
But more important than the biggest states should be the closest states in 2004. I've coded states that Obama won this primary season in Blue, Clinton in Red. Those still pending in black:
New Mexico: -1
Iowa: -1
New Hampshire: +1
Wisconsin: +1
Ohio: -2
Pennsylvania: +2
Michigan: +3
Minnesota: +3
Nevada: -3
Oregon: +4 [update: changed to "pending" from Blue]
Colorado: -5
Florida: -5
Delaware: +7
Washington: +7
Missouri: -7
New Jersey: +7
Virginia: -8
If you were to make the moronic assumption that only the winner of the primary could win those states, that would add up to 81 74 electoral votes for Obama, 49 for Clinton. But better yet, let's look at SUSA's 50 state poll and see how the candidates fared in these states against McCain. I've color coded them Blue for states that Obama does better in, and Red for those Clinton does better:
New Mexico: O +7, C-even
Iowa: O +9, C -5
New Hampshire: O +2, C -8
Wisconsin: O +11, C +4
Ohio: O +10, C +10
Pennsylvania: O -5, C +1
Michigan: O +1, C-even
Minnesota: O +7, C +4
Nevada: O +5, C -8
Oregon: O +8, C -5
Colorado: O +9, C -6
Florida: O -2, C +9
Delaware: O +9, C +5
Washington: O +14, C -2
Missouri: O -6, C -4
New Jersey: O-even, C +5
Virginia: O-even, C -10
Pretty stark, huh? In terms of electoral votes, that's an advantage of 101 for Obama, 74 for Clinton.
No matter how you parse it, the data is clear that Obama is the more competitive November candidate for the Democratic Party.