This beautiful, green, lush park features a lake with tens of thousands of flamingos. Our tour was arranged generally to start from the bottom and go up from there. In my opinion, Lake Manyara was a perfect place to start. Not large enough to be completely overwhelming, the park is home to most of the animals you would expect: elephants, giraffes, zebra, antelope of all types, buffaloes, hippos, monkeys, baboons, and birds of every type. Lake Manyara is also well-known for tree-climbing lions (check out the picture under the hotel page). We travelled in two 4-wheel-drive LandCruisers, each of which popped its roof, giving us 360-degree views. The park also had modern restrooms (which, I found, was a rare instance). Lake Manyara was a good general introduction to the wildlife and environments we would encounter throughout the following two weeks, and I would advise anyone looking to build his own safari to consider starting here. I can't speak from experience, but I have also heard that bird-watchers find Lake Manyara especially attractive.
From journal African Safari--Kenya and Tanzania