Night Owl Cards

I placed an order for one of the three cards I need to complete the 1972 Topps set yesterday. I'm too cheap to order all three at once. But the day is coming soon when I will have completed the '72 set. And that means I'm already thinking about which sets I will try to complete next (excluding the 1956 set, which is an ongoing process that will continue for many years). I've already mentioned that my next top completion task will be tackling the 1973 Topps set. I'm looking forward to that one. The '73 set isn't exactly tough to complete, especially immediately after dealing with the '71 and '72 sets, but it takes a little bit of doing. I like to counter that by tackling another completion quest at the same time, something much easier. I've thought about what that second set will be. If my goal is to complete all the sets from my first collecting period then I should definitely make that second set 1981 Fleer. But I just can't get...