Do Not Be Afraid
Don't be afraid to mix up your rug styles, material and colors. In my home, I have wool Oriental rugs, delicate needlepoint carpets and durable sisal mats all jumbled together willy-nilly, and I think the overall effect works well.
One of the reasons I upholstered my living-room furniture in white fabric was so I could bring in lots of color through accents like flooring. I had a blast scouting for rugs in lots of different hues. In my living room alone I have one carpet in navy, taupe and maroon, a second in blue green and rusty red, and a third in turquoise and tan. Sounds overwhelming, but it's not. Every color in the carpets is repeated in the room's other accessories to create a harmonious, lively space.