You mean I'm not the only one who plans trips around these sites? Cool! I've seen how many sites some people here have been to, and I bow down to your superiority. I am thrilled to see that we have just received our first new site in years - and since it's in my hometown, it's a freebie! I've read that UNESCO believes Canada is already well-represented, in terms of WHS. Nonsense! There is a list of more possible sites suggested by the Canadian government: http://www.pc.gc.ca/progs/spm-whs/itm3-/index_e.asp
I ordered a map from UNESCO of all the sites, and it's up in my office at work (now it's a couple of years out of date). The poster is a great conversation-starter; it gets people talking about all the sites they've been to. Most recently my husband and new daugther went to the Everglades and La Fortaleza in Puerto Rico. Her first World Heritage Sites, not counting the three I visited in Portugal when I was pregnant with her.