TIP: The studio apartment is a good value.
A studio apartment has no separate bedroom. Similar kinds of apartments might be called "efficiencies" or even "rooms for rent."
A small studio apartment is a great option for young people just starting, retirees, or anyone living alone who needs to live efficiently.
The trick to living in a studio apartment is to arrange your living space for multiple uses. Get a bed or a futon that folds into a couch. During the day, your living area is a comfortable seating area, at night, it is your bedroom. Arrange your personal items out of sight in a closet area. Someone visiting you during the day might not realize you have no separate bedroom.
I love the studio apartment I live in. I prefer having everything--my desk and office area, my futon and living area--all in one room. I am more efficient because I do not have to go from room to room to get things. Cleaning a small apartment is quick and easy and heating, lighting, and furnishing it is cheaper.
If you do live in a studio apartment, you should get out a bit more and enjoy the life of the city. In fact, if your studio is centrally located to your activities, you may find you spend your days at work, school, meetings, or enjoy a nearby cafe or museum. The small space of your studio should not contain you at all--in fact, the outside life of the city is much bigger than any apartment you possibly could rent, and so you should go out and enjoy it. If the compact size of the studio apartment motivates you to do this, so much the better.