The U.S. courses I most want to walk are Cypress, Pebble, NGLA, Shinnicock, Pine Valley, Oakmont, ANGC, Fisher's Island and Merion. I'd love to play them, of course, but I'm trying to stay somewhat realistic.
In Canada, my list would include Scarboro, Hamilton, The National and Royal Montreal.
There are plenty in the UK and elsewhere, but I'm starting with the continent I live on...