This has evolved for me over the years.
It used to be my M4 with DR Summicron:
Another from the M4 'Cron combo:
Then with my M8, it was the 15mm Heliar:
Then the M9 with 21mm Super Angulon:
Then I went back to 100% film for a while with a pair of Nikon rangefinders.
The SP with the 5cm f/1.4:
I've gone through a series of digital SLRs for work (two of them were stolen) and the combo I settled on was a D2Hs with 24mm f/2.8 Ai Nikkor:
Unfortunately, that combo was part of the kit which was stolen but things ended up well. Now I have a D3 with a bunch of great lenses but I haven't found my real sweet spot of which lens I love to use with that camera.
Now my real connection is with a Mamiya 6 and 50mm lens but I don't have any of those scanned yet. Soon.
Phil Forrest