I painted our floors this weekend, a pretty grayish-stone color called flagstone by Martha Stewart. I live by the motto "If you can't afford to replace it, paint it." Almost our entire main floor is covered by 35 year old parquet, which is a wonderful, durable, non-dish breaking floor covering, but ours had seen better days. In my dreams we have pretty wide planked wood, or reclaimed brick, or antique terra cotta, but not all dreams are meant to be realized. At least not yet. And so. . . paint.
Here is my word of advice: If you are planning on painting (and polyurethaning) the floors of almost your entire living space, send your four children and your hair-shedding cat away for a bit. Otherwise, it can be sort of tricky. The painting wasn't so bad, but to put down two coats of polyurethane required two late nights with my children banished to their bedrooms for the duration. Try telling that to a two year old who likes midnight snuggles and a cat who has a mind of her own.
We'll see how well it holds up, but I figured the paint would give us at least a few more years.