I was in Kenya for the winter holidays of New Year and I must say that was one of the most beautiful sights I have ever visited.
I think every photographer should visit at least once in your life this wonderful country. Especially for those who love nature and animals, I recommend the safari in Tsavo East National Park.
Here you can see up close many animals that live free in the bush: crocodiles, giraffes, baboons, eagles, cheetahs, leopards, lions, ostriches, warthogs, hippos and many more!
I think the most beautiful animals to see are elephants: massive creatures that get dirty in the red earth of the African savannah, so as to provide photo opportunities you can't miss (in the days where there is serene sky is beautiful to see these huge "red skin" pachyderms as opposed with the blue sky).
I personally had only my compact camera (a Canon G9), but I was able to take good pictures.
However I recommend, for those who own an SLR, a 400mm telephoto lens, but also a wide-angle (for the elephants who eat the grass by the roadside to 2 meters from your jeep!)
Do not miss the occasion to visit the village of the indigenous Africans, called Masai. In reality it is a very touristic place where they try to sell all they can... but you can do a lot of interesting photos, including children and their homes of mud and straw.