I've got all kinds of primes and zooms, but when I'm only carrying one body and one lens, it is usually a motorized FA with a Tamron SP 35~105 2.8 manual focus zoom.
This Tamron is an excellent lens, with nice focal length range from moderately wide to short telephoto, a reasonably fast maximum aperture at 2.8, and it produces photos with good image quality.
And while it originally cost about $1,000.00 +/-, good used copies are available at KEH for vastly less money.
It's my favorite walk around lens.