If you are going to have just one I think the ME-1NV is the obvious choice. Spend the extra $180 and get an FMR compressor for the insert point and you will be set for just about any source.
The 57/ME-1NV combo sounds great and you can play with the impedance and loading to get some slight tonal variations.
Vocals sound very good as well and the DI is amazing on Bass.
From what I understand there is no difference in sound between the one and two channel versions.
As for the mic, I've read great and horrible reviews alike on the Soundelux U195. The cheaper Nuemann's might be a good choice...
Oddly enough, many people SWEAR by the Shure SM7b on vocals...