The World Camera!!!???
28mm, 40mm and 90mm lenses.
Maybe I would leave the 40mm at home.
My recommendation would be not big and not heavy:
Panasonic GH2 + 20/f1,7, 14-42 - best full HD video with autofocus, great image quality at any situation, small, fast, excellent, underwater case Dicapac WP-H10 - optimal choice. I tried on my trip to Mexico, Belize and Guatemala - difficult conditions, no problem.
Sigma DP1 or DP2(s,x) - small package of Foveon (SD15 too heavy) - 3-layered sensor with incredible tonality for extrabeautiful photographic images (excels in good light or long exposures at ISO 100, not suitable for high ISO/low light, slow).
Keeping it real and affordable it would either be my G1 (video not important for me) with a 14-45 and a 45-200 which I already have. If I needed video I would add the G2 body and put one lens on each body. These two would meet all my current needs and them some, but YMMV. At my age I need to keep the camera close to the body for stability and I love the EVF and tilt screen when needed.