A photographers most-used lens is a very personal choice.
That said, I'll give you mine. My most-used lens on 4x5 is a 135mm. I have a couple, one Plasmat and an Ektar Wide-field Ektar in the 135mm focal length for when I need a greater image circle (architectural photos mostly).
I have lenses from 75mm through 450mm including 90mm, 135mm, 150mm, 180mm, 203/210mm, 240mm and 300mm. The one that stays in the case unused most of the time is the 150mm. In the field, I find that I'd rather have a slightly wider "normal" lens; I can easily get the 150mm view by cropping the negative made with the 135mm lens, but not vice-versa.
If I were recommending a lens kit, I'd say go with 90mm, 135mm, something in the 200-210mm range and then augment that with a longer lens in the 240-300mm range depending on your vision and the maximum bellows draw of your camera.
Best,
Doremus