The second phase of McDonald's American Vintage promotion focuses on the 70's and features salsa burgers (Hot and Groovy Beef) and chicken sandwiches (Hot and Groovy Chicken). I don't really associate these with the 70's, but they do look good.
http://www.mcdonalds.co.jp/campaign/americanvintage/index.html
Photo is a web capture for explanatory purposes, copyright belongs to the company.