Nikkor-P 8.5cm F2 in Leica Thread Mount or the Nikkor 10.5cm F2.5 in Leica Thread mount are my favorites. I use them more than the 90/2 Summicron. Both are perfect on my M9 - did not require any adjustments. I use Voigtlander LTM to M-Mount adapters, very high quality. The lenses were less than $400 each, with the adapters.
10.5cm F2.5 album here:
Brian's Album: Spring at Mt Vernon, 10.5cm F2.5 Nikkor
Brian's Album: Signs of Spring, Nikkor 10.5cm F2.5 on the M9
The Nikkor 8.5cm F2 here:
Brian's Album: Nikkor 8.5cm F2
I have the 75mm 1.8, a Summarit 90mm f2.5 and a 90mm tele-elmarit (the thin version). Technically the best lens of the three is the Summarit. And it's cheap by Leica standards. It's also smaller/lighter than the CV 75mm 1.8. But I prefer the 75mm look, which is a bit more classic wide open and then really sharpens up quickly when stoped down a bit. By 2.4 the CV looks as sharp to me as the Summarit.
If you shoot a 35mm then I'd probably get the CV 75mm 1.8. But if you shoot a lot at 50mm then the 75mm is too close for my liking. I'd look for a good used 90mm Summarit.
I too was going to suggest the modern but non-aspherical 90mm f/2.5 Summarit. I've had voigtlander 90mm, 90mm f/2 (fat one), 90mm f/2.8 tele-elmarit and the 90mm Summarit. The Summarit is the only one I have currently. What attracted me was the packaging (small, light), decent build, focus throw, and pricing (by Leica standards). The 90mm f/2 summicron was too large. My sample of 90mm f/2.8 Tele-elmarit had a long and stiff focus throw. The voigtlander was sold before the digital M's were around. I used it on my Epson R-D1 shortly before selling it.
The Summarit's focus throw is short and fairly light. It made for quick focus action and I can go from near to far focus in a single action. Its ideal for the way I shoot. I usually return the lens to infinity or close focus position and quickly turn in a single direction to line up the patch. On the other hand, the fast light action means you have to also be more precise... which takes practice. At one point, I had all of the f/2.5 Summarits, they all have the same feel of a short light focus throw. Only the 50mm was sold because frankly, I had too many 50s to justify keeping all of them.
In regards to FOV, I'm not sure if this is intended on the M8 or M9. On the M8, my Summarit 75mm is usually my preference and the 90mm on the M9. I use a 2x magnifier with the 90mm on the M8.
I gave the 10.5cm F2.5 a workout today. I use the 90mm framelines, and they give me very tight framing.
A very special outing today at the Gulfarium at fort Walton Beach, Nikki was chosen as the volunteer from the audience for the show.
All shots at F5.6.
I am very happy with my Voigtlander 90mm APO Lanthar. Pound for pound I feel its the best value lens I have ever bought. Have a look at my pictures with it in the sample images section.