I have owned every Contax Zeiss lens other than the N-Mirotar and the 1000mm Mirotar and was very lucky to also have their 600 f4 Tele-Apotessar. Having been using the camera system since 1977, the only poor lenses (by Zeiss' high standards but acceptable in use to most people) were the original run of the 25mm AE and the 60mm Macro C (the S is superb). The 25mm was found to be soft and was quietly reformulated by Zeiss and the lens has been an excellent performer since the late-numbered AE types. Unusually, the Yashica 24 ML matches the performance of the Zeiss 25 and costs about 65% less; ditto the 55 2.8 ML Macro outperforms the Zeiss 60 Macro C and the 100 Macro is a close match to the Zeiss equivalent. Leaving the exotica to one side, a great starting kit would be the Yashica 24 ML f2.8, the Zeiss 50 1.4 or 1.7 (if you don't need the extra speed, choose the 1.7), Zeiss 135 2.8 (an under-appreciated little gem) and 180 f2.8 which is sharp and fast. You could also buy a Zeiss Mutar (they really have little impact on optical quality) so that you can increase the reach of most of the lenses and would cover-off the gap between the 50 and 135. You might want to think about substituting the 85 2.8 for the 135 2.8 if you are really keen on portraiture (or the 85 1.4 if you could find one at a sensible price!). An alternative approach might be to buy the Zeiss 28-85 lens, which is sharp and pretty free from distortion at both ends, the 50 1.7 and the 135 or 180. Unless the extra stops are vital, with that zoom, you could even leave out the little 1.7 Planar and use the one lens to cover wide-angle to portrait, and then choose a telephoto.