It really seems to come down to Florida as a necessary but not sufficient for Romney, pretty much sufficient for Obama.
This assumes that MI and PA go blue as I expect.
Florida is one of the handful of US states I have never even been too and only know two people who have ever lived there.
If Obama carries Florida I have Mitt needing ALL of
NV, CO, IA, WI, OH, VA, NC and NH.
Pretty tough odds.
The analyst that has been wrong once since the dinosaurs is this guy Nate Silver guy,
http://fivethirtyeight.blogs.nytimes.com/
The analysis is as thorough a it can be.