Streets wrote:
Mine is my Minolta AF 50mm f3.5 Macro. I love this lens for copying slides and general photography. It is wicked sharp, no matter the f stop. A close contender is my 50mm Pentax Takumar f1.4 SMC which I use in low light and portrait work.
My favorites include the Minolta AF 2.8 mm and 100 macro's, Nikon 60 mm 2.8 D AF, and my all time favorite my manual focus Zeiss Milvus 50mm f/2M ZF.2 .