If following Stu's amazing Luberon itinerary, which villages are worth stopping at and about how long are reasonable stops? Hard to gauge what would be a relaxed pace for touring vs. driving...

I think we spent just a few hours in each of the villages we visited: Ménerbes, Gordes, and Oppède-le-Vieux. That was fine for one day. The next day we went to, and stayed at, Bonnieux, but took a drive up to Lacoste.

In addition to those wonderful places Underhill mentioned, Roussillon with its ochre cliffs and Apt (being larger than a village) come to mind.

We toured the following villages last summer:

Gordes (gorgeous from a distance-a little soul-less once inside), Joucas, Roussillon (charming-lunch at "David" was lovely), Ménerbes, Lacoste, Goult, Saignon, Oppède-le-Vieux (fascinating!), Bonnieux, Lourmarin (the furthest south we ventured),

My three favorites, (though I like all in the Luberon) are Lourmarin, Bonnieux and Saignon. Maribel's suggestion of the restaurant David in Roussillon will reward you with a great view if you are lucky

I haven't been to Bonnieux, but it's my mother's favorite.