I am an architectural photographer who worked with 4x5" film until last year. The lenses I used were the following:
Nikon 90mm f8 -small, light, sharp and with a great image circle (235mm)
Schneider's 72mm XL -heavy, large, with an even larger -and necessary- center filter, but indispensable
Schneider's 47XL and 58XL and Nikon's 65mm f4 -used infrequently, but at least one of them is necessary for those situations where only an ultra wide lens will do the job
I also have Schneider's 110XL, a wonderful lens with a huge image circle (covers up to 8x10"), but for some reason I tended to use my 90mm more often.
Nikon 150mm SW and Rodenstock 180mm S -they are cheap, sharp and have large image circles
Camera: I used an Ebony SW45. Small, light, solid, extremely well built, easy and fast to use and specifically designed for architectural work.
If you are certain that you want to shoot 4x5" film, the camera + 3 lenses outfit I'd recommend would be: Ebony SW45+72XL+110XL+150mm
On the other hand, if you are planning to move to a digital back in the near future, I'd go straight to a dedicated digital solution (Alpa, Cambo, Sinar artec), traditional monorails adapted to digital shooting tend to be heavier, more limited and more awkward to use. And digital solutions, if you buy second hand or negotiate directly with dealers are cheaper than you might think.