Just bought Nik Silver Efex Pro 2. Excellent piece of software. I believe it's the best conversion package out there right now for B&W. Mind you I haven't tried them all, but I don't need to go any further than this package. Presets and control over what effect you want.
Simply great.
This shot was taken using a Pentax SMC 35 f3.5 lens on an E-PL1. I can get some nice results but there are better lenses out there. There should be a gallery up soon with some more images from this lens.