Like Youngin said, what are you going to do with it? If your aim is to ride fixed on the trails, then hell yes. If you are looking for something to cruise the streets with, it will work, but may not be the most efficient thing to do it with. An old ten speed with a flip flop wheelset, decent gearing for your area, and 28's should be enough for most any city riding. The larger tires of a mountian bike might buy you a little cush, but they are heavy, and its rotating weight, so ... Then again, you can generally fit 700x38s in a MTB frame pretty easily, and you can use a road caliper up front, so if you want to ...

-Rob.