Reading your comments "I am not trying to take NG photos as I will not have the equipment for that. I would want shots like Mike took and that ain't gonna happen! I am mostly just trying to take a few shots to show folks back home and grab some memories" .. and
at the risk of throwing a spanner in the works, have you considered a high quality digicam as the backup camera instead of buying another lens. My wife has a Nikon D70 DSLR and a Nikon 5700 - old but reliable (bit like her!). The advantage of the 5700 is that it goes across the full zoom range, is light, portable and provides high quality images. Up to A4, you'll not see a difference in most shots between the two cameras.
In Rwanda, we ended up using the 5700 more than the D70 for pure convenience and the shots were excellent (try getting lenses in and out of a bag, changing them while in a rainforest on the side of a hill with others moving around etc). It would also serve you well in the other locations you are going to (our 5700 has seen service in Tanzania and Vic Falls).
I'd not reccomend the video in Rwanda though - I took a Canon Mvx10i (which has provided great video in the Galapagos and Zambia) but the light was too poor for good quality. I ended up not using it and just enjoying the time with the gorillas.
Whatever you take, have a great time - you'll love all the places.

Thanks for the input. I have the Olympus C750 that does a decent job of it, I think, compared to the 5700. It is digital, with a 2.8-3.7 lens, equivalent to 38mm-300mm zoom, and not bad for a p&s digital camera. It can change ISO from 100-400, which is not great for low light, however. It does little movies with sound and probably the main thing that is frustrating is the shutter lag, which is true of all digital point and shoot cameras, which is what made me switch to digital SLR. At least then it is a little more real time with shots.

At this point, I think I will go with the 75-300 and use the Olympus for the closer stuff and have the camcorder handy for low light.

Hi to everyone,
I've noticed a lot of hits on my Rwanda photos and started tracking them down and found this thread.
If anyone is interested in communicating about shooting gorillas in Rwanda I would be happy to provide information from my Sept, 2004 experience.
I appreciate the kind comments on my photos. This was a "trip of a lifetime" for me and look forward to sharing any information I can to make yours as much or more rewarding.
Mike