What to expect when tearing up carpet?
expect stains, smells, and possibly mastic/glue. 

If you're looking for an 'industrial loft' feel, clean it up the best you can and then just cover it with some high-end concrete/floor paint...or epoxy. It'll be rough, but practical.

For a more finished looked, hire someone with a concrete grinder to grind off the bad top layer of glue, dog pee and what-have you. Come back and then apply an acid stain to the entire thing. When finished, give it a seal coat. That's what we did with our basement floor and, at least for me, I love the look.