Can I install a floor length window on the second floor?
It used to be that such a window had to have tempered safety glass, now:

2006 IRC:  

R613.2 Window Sills. In dwelling units, where the opening of an operable window is located more than 72 inches above the finished grade or surface below, the lowest part of the clear opening of the window shall be a minimum of 24 inches above the finished floor of the room in which the window is located. Glazing between the floor and 24 inches shall be fixed or have openings through which a 4-inch-diameter sphere cannot pass. 

So, no part of the window that actually opens can be lower than 24" unless barricaded similar to balcony railings (4" dia. ball test). Fixed glazing is allowed but must be tempered safety glass if extending below 18" height on the wall. It is easy to order your windows with tempered glass, it just costs a bit more. Check with your window supplier as they will be familiar with the code requirements and any additional restrictions in your area.