When we moved into our house way back, oh, nearly 11 years ago, we pulled up the carpet and exposed the original parquet hardwood floors. They were in terrible shape, but we preferred that to the "renter" carpet that had been in place for the last several years.
But two rooms, the back bedroom and the office, gave us problems. The bedroom's hardwood had been removed at some point, so we had to put carpet in (we couldn't afford the cost or time it would have taken to put in hardwood). And the floor in the office was so bad we felt we'd have to put carpet back in.
We finally got around to putting hardwood in the bedroom and refinishing the floors in the office. Some before and afters:
And the girls' room. More of the same (another 45 degree corner) with two closets and a 13 foot wall, this one took longer, but it all came together and the kids are thrilled with their new floor.