I would go for a 35mm Summaron, or a budget Summicron like the one DF mentioned-2nd version??
Personally I would steer you far away from 3rd party lenses for your new M. Not to say many of them aren't superb, but that can be a long road that usually leads you back to Leica glass which can often be had for what is ultimately not that much more money, and a whole lot less hassle. Find a good user Summaron and you'll sleep better at night.
as mentioned the VC are good lenses, personally I used the 35 ultron for about a year on my M6... excellent quality I must say and unless you judge every picture with a 10x loupe I think it will serve you well.
It also depends a lot on your style of photography, I like OOF/Bokeh or whatever it's called, in this area the Ultron is rahter harsh (personal) and during the year of use I found myself shooring more and more a open apperatures and appreciating the OOF area as a counterpart to the actual image. I tested the 35mm asph summicron and the CZ 35mm 2.0 both for a couple of days and found that the Carl Zeiss meets my expectations so I bought that one and am pleased with it.