While there are plenty of sets who's designs I like enough to collect, I'm going to limit this to sets that I like enough to collect and actually have some.
1969-1970 Topps Basketball
What I don't like about it: Odd size requiring 6 pocket pages. That Kareem RC is the type of thing I am trying to avoid by diversifying away from baseball. 13 cards have BV greater than $100
1971-72 Topps Basketball
What I don't like about it: Not a huge fan of all the yellow on the back, but at least it is readable
1972-73 Topps Basketball
1971-72 Topps Hockey
What I don't like about it: Egads! That back is ugly