Here's one that a lot of collectors completed. In 1989, I came very close to finishing this set simply by buying packs at one drug store. I came 4 cards short. Finished the set years later when got back into collecting. Also, I might have a second set in a box somewhere!

For my 100 streak badge, what's better than my all-time favorite set? I started in the hobby buying packs of 1975 Topps, both the regular size and the mini size. Today both sets -- 50 years old this year -- are complete ('75 in 2004 and '75 mini in 2014)

The 45th anniversary of this set, Kellogg's went with even narrower cards than its 1979 set. But I never have to worry about cracking with these.

First and last full page in the 2009 Upper Deck OPC set. I liked this set right away when it came out. Even considered collecting all the black parallels but eventually ditched that.

The 1983 Topps Glossy Send-In set was the first of its kind and was a yearly issue by Topps from that point through the '80s! I remember sending in those wrappers to get these cards! I completed the set last year.