Best defense - 1983 Raiders or 1985 Bears. Raiders had an amazing secondary (Hayes, Haynes, Davis) and the Bears had top defenders at many different positions (Dent, Singletary, Marshall, Hampton). Honorable mention to the 2000 Ravens.
Best offense - 2007 Patriots. 49s from the 80s (Montana, Rice, Clark, Craig) and Cowboys from the 90s (Aikman, Irvin, Novacek, Smith) are also a solid choice.