My boyfriend and I started in the N. Serengeti ((Mara River & Lamai Triangle), through the Central (Retina Pool,
Seronera Valley, Makoma Hill, Maasai Kopjes & Sametu Kopjes), then onto the Ngorongoro Crater - over 9 days. Time of year - Aug 2010 (tail end of the Great Migration).
Highly recommend if you want to see large quantities of game. We saw a Wildebeest crossing (thousands crossing a river), loads of Hippos in the river, large groups of elephants, zebra, buffalo, and so much more!
To truely get a sense for how vast and variant the animals, weather, culture, and life is across the Serengeti - do a cross safari trip.