In a fit of annoyance we decided to ditch it. The problem was we needed to do it on the cheap.
My first thought was to rip out the carpet and sand, then paint the subfloor and leave it like that until we had enough to put in hardwood floors that matched the rest of the house. The downside to this is that there is nothing between you and the ground and without any protection other than the paint you might damage the subfloor and need to replace it (not something I wanted to do).
The other idea I had was to lay down plywood over the subfloor and paint/finish the plywood. I'd seen this in some lofts and thought it looked pretty good. This is what we decided to do.
We had two simple goals - put something in that looked better than the ugly carpet and for as little as possible. I think we definitely achieved this and the total cost around $400.00.
The best thing a about doing your floors like this is that down the road if you want to upgrade and install hardwood floors you don't need to pull up anything - you can install them right on top.