Note for self-reference and for others: here's my thoughts on the equipment I brought for the trip to Africa.
- 10-22mm: barely used it, but the shots I got with it turned out excellent. Must have.
- 18-200mm: useful to create memories, not for making brilliant photos cause the quality is quite poor compared to the other lenses I brought. Still invaluable on a trip though. Definitely bringing this for the next trip, wherever I go.
- 70-300mm: This one was absolutely necessary for taking pictures of wildlife. It was pretty much useless for anything else though, as I expected before I left. If I was going on a city trip I'd probably leave this one at home though.
- 50mm 1.4: Useless! Nice if you're doing trick shots but quite pointless on a trip. Leaving this one at home next time. Night shots were not worth it either because it was too dark and difficult to focus on the subject.
- 50D over the 400D: good! I am glad I brought the 50D. The custom modes were ok, but in the end the higher ISO and increased resolution are the main reasons for preferring the 50D. The weight didn't matter much at all because we traveled by car for 99% of the time.
- Tripod: didn't need it at all.
- External flash: missed it for one or two portrait shots with backlight, but I'm not sorry I left it at home. Perhaps I should get a smaller flash instead.
Tip for the traveler: always bring a spare battery and memory card! You never know when one will fail or run out during a trip. I also brought a compact camera, which was invaluable for taking movies, and for taking pictures in areas that were too dodgy to take out the big camera.