Well, Yahtzee didn't rape it up the bum with a pointy stick. Either that means it's good, or Beth slipped him an envelope full of cash.
http://www.escapistmagazine.com/vide.../420-Fallout-3
Many, many arguments on the official forums about whether it can be called a true sequel. I can't wait to try it out, even if i already know which camp i'll fall into.
As for the original Fallout, it's an RPG classic. You're mad if you don't hunt it down.