One of my favorite lenses on my 35mm Contax was my 25mm wide angle. After I purchased my Tachihara 4x5 I picked up a 75mm lens since I read that you take the focal length you like for your 35mm camera and multiply it by three and it will give you a rough equivalent. Well, the 75mm lens felt too wide for me, more like a 20mm lens on 35. I replaced it with a 90mm and have been very happy.

What focal lengths you end up using on your 4x5 camera may not be the mathematical equivalents of the lenses you now use on your 35mm camera. With me it took a little trial and error to find what I like. Fortunately you can buy used lenses, try them out, and them resell them for close to what you originally paid. I just figured the little money I lost as a cheap rental fee.