I've been saying this for a while, nice to see it confirmed in a poll by Time:
Obama captured 48% of the vote in the theoretical match-up against McCain's 41%, the TIME poll reported, while Clinton and McCain would deadlock at 46% of the vote each. Put another way, McCain looks at the moment to have a narrowly better chance of beating the New York Senator than he does the relative newcomer from Illinois.
The difference, says Mark Schulman, CEO of Abt SRBI, which conducted the poll for TIME, is that "independents tilt toward McCain when he is matched up against Clinton But they tilt toward Obama when he is matched up against the Illinois Senator." Independents, added Schulman, "are a key battleground."