When I first saw all the 3.0 stuff, I thought that they were using all the best house rules as parts of the core game, this time out. I felt like they didn't go quite far enough, though. I like to take the coolest elements that I can find from each set of the rules and mix them up to get something that allows for the players, and myself, to have exactly what we want in a given situation. We throw in a lot of stuff from other systems and game worlds, as well as distilling stuff from books and movies as much as we can, too. The game has become just one big houserule, for us.
A lot of the stuff we have used has come about because we wanted some mechanics that reflected the story and whatnot, like racial and class abilities being done in different ways for each race/class. I don't know anyone who actually uses 3.0 or any other system RAW. I did like the "37" answer, though. Even if it's not accurate, it's still funny.