Excuse me for throwing a spanner into these works. Buy a 35mm. Learn to use it. You will probably never look back.
When I had Leicas (a long time ago!) I started out with an M2 and a 50/2.8 Elmar and then bought, in lightning-speed succession, an M3 and a 50/1.5 Summarit, a 50/3.5 Elmar, a IIIg with a 50/2.0 Summar, and lenses- 35/3.5 Summaron, 90/4.0 Elmar, 135/4.0 Hektor and 200/4.5? Telyt lenses with all the hoods, filters, close-up devices, and the rest. My bank manager loved me, as I borrowed most of the money to buy the above, from him.
In a very short time I found I was using almost exclusively, the 35 Summaron (most often), 50 Summarit (about a third of the time), and 90 Elmar (now and then). I used the 135 a handful of times, I think, and the Telyt only once before it was stolen from my car. Insurance paid out but I never replaced it.
The 35 with an adjustable finder will cover a lot of territory. Summarons are delightful lenses to shoot with, whether the 3.5 or the 2.8 version, whichever suits your budget best. They are very much the same, and give lovely not too hard definition and creamy mid tones and colors closer to pastels than the more harsh Fuji and Kodak Technicolors we look for nowadays.
The 50s are okay but somewhat too limiting for my viewpoint. Of my three standard lenses, I think I loved the Summarit most of all. It was a screw mount lens made in the mid 1950s for the IIIf and IIIg. I used it more than any of the other 50s,in fact whenever I shot in available light it was my preferred go to lens. It always delivered the goods.
All these beautiful cameras and lenses are long gone. Fiscal realities intruded in my dream world and I had to sell the entire lot to cover home emergencies. I miss my Leicas, but nowadays in my retirement, I realise I'm too old and wise (and let us not forget poor) to make the big bucks investment in all this gear. Even in the '80s Leica stuff wasn't cheap, but at least I had the money then. I don't now. (Sighs heavily.)
