Well, there is one thing that we all should remember when calibrating our camber settings. How well does the car handle while gripping? If you have a car that tends to turn in well and can handle a relatively decent amount of "over correction" then there is really no point of camber "correction" or adjustment.
However, if you have cars that are understeer heavy (such as the S13s, FC's and AE86s)a slight camber correction may be understandable. Conversely, cars that oversteer without much effort (as the above mentioned Supra or the 300ZX or S14) then camber, as far as drift input, shouldn't really be something that worries you.
Camber is one of those coup-de-gras modifications that you really shouldn't worry about in any car. I mean, since it's a game and these types of adjustments are easily adjustable and readily available, then I'd say experiment and play with what works best for you. But I'm positive that if you run stock camber, you'll be able to drift just fine in the game or in real life.
-Dave