QUOTE (dspeed @ Sep 13 2009, 04:43 PM)

The primary goal is relaxation, the secondary goal is photography/tourism. Gastronomy is third.
Third only? Wee, strangers are sooo strange...

But welcome to France anyway!
To be more constructive, I can only point you to
this thread that you've probably read.
A local remembering : if you like sweet-but-not-harshly-sweet white wine, go for Saussignac (15km SW of bergerac) and look for the vineyard "Court les Mûts" of Pierre Sadoux : his "vendanges tardives" (late harvest) is outstanding (to the same level of quality of well-heeled Sauternes, imho).
For the color peak, as the summer has been quite dry, it may be a little early, the beginning of October might already be good - hard to tell from now.
If you
really aim at those colors, go for the early side, and if it's too early in Dordogne, take a few hours drive to the south to the Pyrénées?