Don,

Another thought is soft water. Is the water in your area pretty hard? If so, it may be worth putting in a softener (and your wife will love the feel it gives her hair!!). I have the same problem when I'm in Vegas. The water there makes me wash the car at 6 am so I have time to wipe it down before it spots.

As for equipment, 4mula had a good suggestion, and I also like a VERY soft terry towel (and the soft water will help these stay fluffier too). I've got a couple buddies who swear by those soft squeegies that California Car Cover sells, but I haven't used one. For some reason I have in my mind that they increase the potential for scratches, though I have no proof. But then, so does a dirty chamois or towel.