faris,
What other lenses to you have? If I were to build another M system with Leica glass the 75 'Cron would be my tele of choice. Size and quality is second to none and it's fast enough to do some existing light stuff when I want to reach out a bit more. Do a 35 'Cron (VI if you can) or a 28/2 CV and 75 'Cron and you're set.
Please do not get me wrong, I love my old 90 'Cron, she was a GREAT lens, but if I started over again it would be the 75.
B2 (;->