Vertical Blinds
These blinds are commonly found in homes built in the 80s and 90s- and I can understand, kind of, why once upon a time someone thought these were a good idea. They are easy to pull back all in one swoop, and they can block out light decently well.
However, anyone who has lived with these blinds can tell you they are not always so easy to manage. One of those suckers bends in half and it can ruin the look and functioning capability of the whole bunch. Some curtains will do the trick just fine and will give your room a softer and more sophisticated look too.