I think it is really important to consider the size and style of the house when selecting finishes and furnishings.
You mentioned hardwood floors, so start with area rugs. It is much easier to choose a paint to match a rug than a rug to match paint. Find some rugs that fit your taste and the house style. Wool rugs are expensive but wear like iron, nylon rugs are cheaper. Some nice rugs here
shaw rugs.
When selecting wall paint it helps to have an idea on the direction you want to take the house. If you want a lot of different colors consider what can be seen from one room to another. Use the same trim or ceiling color to tie things together. Bright colors make rooms feel bigger and dark colors make rooms feel smaller. Lights, furniture, art, etc can counteract the affect of wall colors. If possible get large samples of paint colors and look at them in the room and on the exact wall you intend to paint that color, don’t underestimate how different lighting can change a paint color. Don’t be afraid to paint walls different colors within the same room.
For furniture I feel the style should be consistent with the home. A bungalow calls for Stickley or Limbert while a modern loft would look better with Nelson or Eames. Regardless of style, typically you want light furniture in small rooms and heavier furniture in large rooms. By light furniture I mean pieces with less visual weight, open to the floor, thinner legs, and generally more delicate proportions, think feminine. For large pieces like sofas avoid busy patterns in favor of neutrals and accent with pillows. Smaller occaisonal chairs can have bold patterns.