It appears that Obama is doing just fine now that Hillary is out of the campaign:

Barack Obama’s recent gains in general-election polling against John McCain have come in part from a widening advantage among women. Obama now leads McCain by 51% to 38% among women overall, and has overtaken McCain among older women, a core Clinton constituency.
Gallup.poll

Illinois Sen. Barack Obama, the likely Democratic presidential nominee, has pulled even among white voters with Arizona Sen. John McCain, the likely Republican contender, and now tops Sen. McCain 50 - 36 percent in New York State, according to a Quinnipiac University poll released today.

Sen. Obama gets 42 percent of white votes, to 43 percent for Sen. McCain. Black voters back the Democrat 87 - 6 percent. Obama leads 59 - 29 percent among voters under age 45 and 45 - 40 among voters over 45; 45 - 40 percent among men and 53 - 32 percent among women.

This compares to a 47 - 39 percent Obama lead over McCain in an April 18 poll by the independent Quinnipiac (KWIN-uh-pe-ack) University, when New York Sen. Hillary Clinton still was in the race. In that survey, white voters backed McCain 48 - 38 percent.

While it was a tight race between two 'very well liked' Democrats, it's an entirely different story when you put a Democrat up against a Republican.