I've been told by some FReepers that Murrica is still too racist for a black President. I dunno, I view the world through the eyes of a New Yorker, so I'm not seeing all that racism. Murrica? No, not in my opinion. She'd carry PA and MI and WI and MN to offset any losses due to racists in the red states. Louisiana, though? Definitely.
What Condoleeza Rice would pick up in suburban Philadelphia she would lose in that state's "T-zone" with white Catholic, German Protestant, and Scotch-Irish evangelical voters. What she would pick up in suburban Detroit she would lose in Dutch Calvinist western Michigan, which is usually strongly pro-GOP. Republican margins would decline sufficiently in historically Republican central and western Ohio to offset any "soccer mom" gains around Cleveland and Columbus. Not only would she not pick up PA or MI, she would lose OH. Her candidacy would reduce GOP margins in northern Florida without sufficient offset in Orlando or elsewhere. This is especially true if Evan Bayh receives the Democrat nomination.
She might do better in WI and MN than did Bush. Her candidacy might even help GOP fortunes in MD, DE, and NJ. However, she and Bayh might wind up splitting the South and she would probably lose OH.