The best song that was left out of "Blackout" is "state of grace", thats what I call a masterpiece song, I don't even know what was Britney and her team thinking when they didn't include it on the tracklist.
if "state of grace" would've been included, "Blackout" would be even more epic and amazing.
I guess this is the difference between Britney and Madonna, Madonna would never ignore a song like this she knows whats best .... but Britney sometimes just doesn't see whats best for her.