William -- NEX-5 & Rollei 50mm 1.8 HFT.
Sometimes I ask myself if I really need all those 50mm lenses that I never seem to be able to stop buying. The 50mm f1.8 lens, which I find to be a perfect compromise between price and performance, especially for the Rollei QBM 50mm f1.8 FHT. This is a ridiculously sharp lens, especially from f2.8 on. In most cases, it's hard to tell pictures taken with this lens and the Zeiss 50mm f1.4 QBM mount at any aperture from f2.8. The Rollei 50mm f1.8 seems to have slightly more intense colour saturation, whereas the Zeiss Planar 50mm f1.4 QBM is a bit more neutral. Both a great lenses, but we all know which one wins the price to performance ratio.