Open savannah. Everything's is here, you've just got to look.
The elephant park. Beautiful Baobab trees are everywhere, giraffes and zebras. Spot the dik diks in the undergrowth
Seems like the cradle of life. ALl the animals are effectively landlocked enabling you to get close. The wilderbeast migration comes here for the lush green grass. All the big 5 are here and as a 'one stop shop' you should be able to tick them all off in a day
The National Parks
All the parks have a different feel, size, animals present and accomodation possibilities. You need to factor in transfer times as Tanzania is a big country! For instance allow a whole day from Arusha to get to Ngorogoro - you're unlikely to get a long game drive the same day