While nearly every place I've yet anchored is probably covered in the guidebooks, I will say for seclusion and peacefulness, any place south of Point Lookout and north of York River wins for those of us doing most of our sailing on weekends.
Yes, there are many great destinations in the mid-bay, but there are far more powerboat wakes up here to upset things (Eastern Bay for example) and you are highly unlikely to have an anchorage to yourself or shared with one or two other boats which was common when we were sailing out of Deltaville. As an example, I counted over 50 boats anchored/rafted in Shaw Bay on a non-holiday weekend. Fishing Bay in Deltaville is similiar in size and was considered crowded if there were a dozen boats.
I envy those of you in the mid-bay that are able to get in some overnights during the week where there are less wakes to contend with and fewer boats in the anchorages, but I really envy the folks that are able be close to their boats and sail out of the Middle Peninusla area.
s/v Palmetto Moon
1991 Catalina 36