I'm busy planning a quick trip to Kenya at the end of November. It's a good time of year to travel as far as flight deals go. KLM has some of the better connections from the US, and they just announced a sale. You can get from LAX to Nairobi for under $1200. (Note that a "good connection" for a flight from the US to Kenya means you'll be traveling for at least 20 hours). South African Airways is pushing their flights to Kenya, but it's a hard sell psychologically as soon as you look at a map. Turkish Airlines has the best prices (even without a sale) and the connection is wonderful, especially if you fly directly from their hubs in Chicago, Washington DC, LA, or NY. Make sure you check the flying time though, it can vary quite a bit depending on the day you travel.
Ethiopian Airlines is giving everyone a good run for their money, and the Addis Ababa connections are good. Their new Boeing Dreamliner direct from Washington DC is an added bonus. But the late morning departure makes it difficult to make a same day connection for those of us not living on the East coast. Emirates via Dubai and British Airways via London have great connections, but generally higher prices to match.
Of course I was looking at flights before any of the airlines announced their sales, and ended up using miles to get myself to Nairobi. While it's a cost effective strategy, it's a little insane. It'll take me 32 hours or so to get from Denver to Nairobi, with four stops along the way. My return flight will also involve 4 stops, but I get to sample the Dreamliner. Stay tuned to find out how that goes.