If you're worried about losing direct ad sales to AdSense, why have AdSense on your pages at all?
On my site (and, I suspect, on many others), AdSense ads serve different markets and different purposes than other types of ads. I don't even want to get ad inquiries from the guy with a B&B in Widgetville, the travel agent who's selling Elbonian inner-tube cruises, or the general advertiser who wants to buy 10,000 text-ad impressions across the site. If Google can sell ads to those people and send me some of the impressions and clicks, more power to them.
Still, why do we continue to fight this battle in a Webmaster World thread? The feature is gone, finis, dead--at least for now. RIP "Advertise on this site."