Well I normally only carry 2 Pentax lenses a 50mm and a 28mm for my camera, I do use a a Series 1 f2.8 Vivitar 70-210mm for concerts etc
But by choice the third lens I would include would be a Tamron SP 19mm, mine went into a canal 17 yeras ago and although repaired, it flared afterwards.
If I could afford it better still a 21mm Leitz lens for my M3. I was loaned one for a couple of months and the differance in quality - lack of distortion compared to a similar lens for an SLR is - is incredible. But as all my serious work is now shot on 5x4 I use the equivalent focal lenght a 65mm Schnieder when I need to.
A pair of lenses with a woman wearing them(who wants to be alone on an island for years?).That being said I'll take any three Sigma EX zoom lenses covering all the focal lengths I need-the bigger question is where and how to develop and store negatives.
"An object never performs the same function as its name or its image"-Rene Magritte
"An image of a dog does not bite"-William James applied to photography
I only have 3 lenses for my Nikon now. All zooms and the three offer a huge range - AF-S 17-35mm f2.8D, AF-S 28-70mm f2.8D and AF-S 80-200mm f2.8D. I also just bought the new TC-20E II AF-S teleconverter. This combination gives me me a range from 17mm to 400mm in 4 lenses.
It would depend on the camera I have with me. If I had a Leica rangefinder, I would want the 21/4 Voigtlander, 35/2 Summicron and 50/2 Summicron. If I had a Canon EOS SLR, I would want my 20-35/3.5-4.5, 50/1.8 and 70-200/2.8 (hopefully with Canon's 1.4x and 2x extenders). Can I have all of it? With my medium format equipment, too? Please?