I voted one, and I very often do just that. Not always, but more lately.
I have identified, for several of my cameras, which lens is the *best* lens to use with it. For example, with my Leica M4-P, I use an Ultron 35mm. At f/1.7 it's fast, and it's versatile. The 35mm focal length uses the second to largest frame line in the viewfinder, so it maximizes the VF, while giving me just enough sight of what is just outside of it.
On my Nikon FG, I use a 43-86mm f/3.5 Zoom Nikkor. One of Nikon's first zooms, it's funky (a push/pull at that), full of character (some say it's Nikon's worst lens ever) and well made. Plus it's a useful range.
My Nikon N80 wears a 24-120mm f/3.5-5.6 G VR lens. A very high tech system, and since the N80 is so light, easy to carry all day.
On the D100, I use the 35mm f/2 Nikkor. It's a perfect normal lens for the APS sized digital sensor.
My Nikon F5 almost always has either the 60mm f/2.8 micro, when it's on the copy stand, or 85mm f/1.8 when it's shooting portraits.
My Mamiya 645 is mated to it's 110mm f/2.8. Looking through the prism finder with that lens, the view is exactly the same as with the naked eye. A perfect medium format, shoot it as I see it lens!
And last but not least, I shoot wide with my OM1n and 21mm f/2 Zuiko. It's my favorite indoor lens of all time. I love being able to shoot an entire room in one shot. Once in a while I am tempted to put one of my other Zuikos on it, like the 50mm f/3.5 macro or 100mm f/2.8 but that's just a passing fancy, I always go back to the 21. I love her!