40mm Minolta Rokkor-M ~ not too big or expensive ($400), takes regular 40.5mm shades and filters, excellent build, nice bokeh, smooth yet sharp, in between a modern and a vintage lens, great for B&W, prefer it over the Summicron.
The 35/2.5 VC M lens is well built and renders nicely too, same league as the Rokkor.
I did not like the 40/1.4 VC but IDK about the 35/1.4 VC.
The 35/2.8 Summaron is quite wonderful, it is one of the best built Leica lenses and it renders beautifully.
I've had the V.3 Summicron and it is very good, about like the Rokkor only with a concave tab ;-)
I've also had the old Summilux and the ASPH Summilux. You (and I) can't afford them but they are sweet.
I wouldn't be afraid of a f/2.8 lens in low light. When you shoot a f/1.4 lens in low light you get a lot of focusing errors, so it is almost a toss-up whether you get the shot or not. I rather have it render well and stop shooting a little bit earlier. The main reason for getting a wide f/1.4 lens is for subject isolation, so you ought to be doing a lot of near-far subjects to rationalize those faster, expensive lenses.
I might get an old 35/3.5 Summaron someday if I find a clear unhazy one. I like the size most of all.