Home is where the heart is, but hopefully not the mold

So signs are pointing to this august I will be moving into a house shared with a few other girls. They are looking for houses in the area, and are going to check out one of them today.

When looking at a house that you may be moving into for a year or so, what things should one check for? Aside from obvious things like "mold coming through the walls," what are the tell-tales?