Hmm...funny you would mention this. Bush's lead over Kerry averages about six points in the latest national polls -- which, if anything, may be slightly conservative (at least until Gallup says it's closer -- I trust Gallup over every other firm and have done so for decades).
As someone recently pointed out, Rasmussen had the race in New York closer than the race in New Hampshire. If that didn't set off a red alert about the reliability of his methodology, nothing will.
I haven't seen the internals for the state polling data but if he uses the same weighting for NY then having a 39% Dem to 34% Rep may explain why so close. I would think NY would swing Democrat in turnout much more than the national average....with that being said he may be underrepresenting Democrats in New York and OVER representing them nationwide.