The main focus of our trip was seeing primates (mountain gorillas, chimps, & monkeys), for which Uganda is unparalleled. But you can see a lot of other classic African wildlife too. We saw 11 lionesses, scores of elephants, hosts of hippos and buffalo (and, thankfully, zero snakes).
Perhaps the most unusual non-primate encounter we experienced was seeing a lion climb up into a fig tree, relax, hang out, jump down, and then climb back up again. This was in the southwestern corner of Queen Elizabeth Park, in a place called Ishasha (clic the pics for a more glorious image):
I climbed up onto the roof of our Land Cruiser and was almost eye to eye with her!