It partly depends on when, length of vacation, drive vs fly, finances and the like. Things that come to mind are Williamsburg (several nice resorts and easy to get), Boston (Marriott only), HH (Marriott's,
DVC), Caribbean (easy for summer), Cancun (esp the Royals), Branson (easy to get and lots to do), CA Desert (HOT in summer), Tahoe (up and coming), Rockies. As for resorts in the II-DVC list, I'm not with the list right now so this will be from Memory.
From a specific resort stance, I'd say many of the top Marriott's would fit the bill. Hyatt's in Key West, anywhere on Captiva or Sanibel, Marriott or Williamsburg Plantation there, Franz Klammer Lodge, Park City Marriott's, St. James CO, Marriott's and Hyatt's in CO and Rockies, many HI places, Paradise Village in Puerto Vallarta, Royals in Cancun. I'd even put North Carolina Mountains and Gatlinburg as good spots. Caribbean would be best for Harborside in Bahama's, several Aruba properties, Grand Caymans (2 resorts), Puerto Rico (? Hyatt), Westin St. Johns. I'm sure there are others I wish I'd have mentioned once I get through.
Give more info and we could offer more appropriate suggestions. Good luck.