Curtains are a great idea for areas that you want to separate, but still want light to travel through. Curtains made of a transulcent-type fabric are the best way to achieve this effect. But for more private areas, like your bedroom, you might want to consider a more substantial room divider. Go to http://www.modabode.com/Room_Dividers - lots of styles of room dividers to choose from - even super stylish Shoji sliding screens.

Also, try to variate height levels of your room dividers. This creates more depth and visual interest.

Have fun decorating! 

Hey there! I actually think that I might have an idea for you that will work. The apartment I'm moving into next year is actually only a one bedroom, and my roomie has that room. However, I really got the better end of the deal (in my oppinion) because my room is actually part of the living room, but it's divided off by a screen. Lucky for me my roomie is cool and never uses the living room, so I have it all to myself really.

Anyway, my point is, you can do A LOT with bookshelves and folding screens. That's how mine is set up. We have a small bookshelf that faces into the living room (so it's still decorative) and then a folding screen. Together, they block off my side of the room. Now, depending on how long your room is, you might have to have your bed area be more like a bed nook, but this could be kind of cozy (in my opinion)... you can hand pictures and such from both sides of the screen, and if you set to bookcase facing your "lounge area" you can have all your books right there next to your chair. It's very functional, and inexpensive.

Also, you might try posting pictures of how your room is now to give people more to work with.