POMEROY, you will not find a higher correlation to the final lines in any American sport then Pomeroy, and that’s saying something, because with 300+ teams getting the numbers that close is pretty damn impressive. It’s rare to see the Pomeroy line even 2 points off the opening number. Also has totals, must have for any NCAA BB fan or handicapper.
Fangraphs, Best MLB site on the internet hands down, Baseball Prospectus might battle for that title but fangraphs has much more useable data. Dailybaseballdata is also good for certain data.
Footballoutsiders.com is the best NFL sitem same people who run Baseball Prospectus
Teamrankings is unique as it’s the only one I’ve seen that maintains a histroical database of the rankings prior to each game. So if you want to see the rankings for NFL teams as off week 2 (which would be a hell of a lot better for predictive purposes then current ratings) You could do so.
MrNFL is good database for NCAA and NFL football data
NBA, I would look for sites focusing on Hollinger/Oliver based stats, 4 factors, pace, etc. That is what drives Pomeroy.