Bird, Wildlife, and Landscape kit:
EF 300mm f/2.8 L II IS
EF 70-200mm f/2.8 L II IS
EF 16-35mm f/2.8 L II
This assumes that teleconverters are allowed, in which case I'd also have the Kenko 1.4x DGX and EF 2x III TC's. I think that would cover most of my needs. Focal lengths range from 16mm through 400mm without gaps when factoring in the teleconverters, plus 420mm and 600mm. If teleconverters are disallowed:
EF 600mm f/4 L II IS
EF 100mm f/2.8 L II IS Macro
EF 16-35mm f/2.8 L II
I'd like to have the MP-E 65mm f/2.8 1-5x as well, but as a niche lens I don't think it would be as versatile as the 16-35mm and 100mm f/2.8 macro lenses.