I haven't been to that many zoos, but one of my favorite exhibits is the Watani Grasslands at the North Carolina Zoo. The main part is 40 acres and contains Southern White Rhinos, Fringe-eared Oryx, Mountain Bongo, Sitatunga, Thomson's Gazelle, Common Waterbuck, Addra Gazelle, and Greater Kudu. Up until a couple weeks ago, it also had an ostrich. There are mud wallows for the Rhinos, sand piles for the Addra, and trees that provide shade. In addition, there is a large wooded area with streams behind a small fence that borders that main area. This keeps the Rhinos out, but most the antelope can go through. There is much viewing into the woods, so it can be difficult to see the Bongo and Sitatunga (who hang out there a lot). You can also take a 40 min. to an hour tour through the exhibit on a bus. This is called Zoofari and only costs $25 a person.