Personally, I would hesitate to put tile throughout a main floor in a cold climate. We live in the far north and have tile in a bathroom, but not anywhere else. Even if you don't mind it, I know that I would think twice about buying a place that has tile everywhere.
We had the same issue as you with a mishmash of poor-quality flooring types when we bought our house. We pulled it all out and put in wood-look vinyl plank flooring across most of the main floor (kitchen, LR/DR, and entry). I love it. It really ties the whole main floor together, it's easy to maintain, and it feels pretty good underfoot.