Best fluff of all the 3.5 And 4th books?

[Starscream]

Not a whole book, but my favorite bit of D&D Fluff of all time is the explanation in RoTW for why a race that worships a Lawful Good deity like the halflings tends to produce so many thieves and scoundrels.

Seems that back in the day, Yondalla had a bit of a naughty side (not like that, you pervs). When it came time for her to create a race, she couldn't decide what their theme would be, so she stole the bits she liked from all of the other races (adaptability from humans, courage from orcs, loyalty from dwarves, free-spiritedness from elves, etc) and infused them in a pixie to create the first halfling.

The other gods were ticked off that she had robbed them, but Yondalla smooth talked them out of punishing her by claiming she just did it because all their ideas were just so darn good. So all the gods did was force her to to remove the larcenous streak from her own personality, leaving her pure LG forevermore.

She did, and it became a deity itself named Dallah Thaun. DT is Chaotic Neutral, but because she is from a part of Yondalla they share the same thoughts and memories. They are literally two side of the same being.

So ever since halflings have been able to be CN while claiming with a straight face (even under magical compulsion) that they worship a lawful good goddess. That is an awesome explanation for their cultural tendencies, and one reason I love playing halflings.