It doesn't matter what past Fallout's have been. It's in the hands of a different developer with a different set of values. So whatever qualities the storylines of the other two games have will probably have no relation to how Fallout 3 turns out.
But if you're interested I'm sure it's pretty easy to find a plot overview of FO 1 and 2. All I can say is that what it's not what it's about, but how it's about it. Don't expect reams of technical information like the MGS series.
Another thing. Fallout 2 had an overarching storyline, but each town/city/area had it's own plot line with relevant quests. Many NPCs had their own plotlines as well. You really can't compare it to many games out there, because the way it approaches storytelling isn't mainstream in the least.
Frankly, Fallout 3 is shaping up to be a mere shadow of the old games, lacking the attention to detail, complexity, and wit.
