ANyhuis, I'd love to see your 26 through 50 list! Do you still have it? I imagine it has changed since printing the 1 through 25!
I never actually finalized my list from 26 to 50. But I can tell you what exhibits were in contention for the bottom of the 1-25 list (and thus they'd be sitting there in the high 20's:
Maharajah Jungle Trek (Disney's Animal Kingdom)
The RainForest (Cleveland Zoo)
Tropics Trail (Minnesota Zoo)
Gorilla Tropics (San Diego Zoo)
Tropic World (Brookfield Zoo)
Northern Trail (Minnesota Zoo)
Minnesota Trail (Minnesota Zoo
Dolphin Adventure (Indianapolis Zoo)
Wings of Asia (Miami Metrozoo)
JungleWorld (Bronx Zoo)
Northern Trail (Woodland Park Zoo)
Asia Trail (National Zoo)
Tropical Asia (Woodland Park Zoo)
And had I seen them prior to making this list, I likely would have put Columbus' Asia Quest and Manatee Coast on this list too. My biggest regret is not putting Minnesota's Northern Trail on my list.
The way I did this was to first do a statistical analysis (I'm a professional statistician), factoring in many factors: (a) Rarity of animal species; (b) Number of species; (c) Number of animals; (d) Uniqueness of exhibit; (e) The "Wow!" factor; (f) Viewing availability/ease of animals; (g) Comfort and care of the animals; (h) Time and value of touring exhibit; (i) Theming; and (j) Year-round access. For each of the above categories, I gave the exhibit a score from 1 to 10 (most of the best exhibits got 8's or higher). I averaged these scores, put the exhibits in order accordingly, and then finally did some minor subjective reordering according to my personal opinion, Jon's opinion, and an informal survey I took of a dozen or so people.