I almost forgot! NO OVERHEAD LIGHTING! Overhead lighting sucks, so try to pick up a few sweet lamps from Ikea or something or put a large tapestry on the ceiling over the main light. Also invest in a dimmer switch. There are ones you can put in the wall, but since you're renting, you might just want to stick with the ones that you can plug the lamp straight into. They sell them at Wal Mart for about $9. VERY useful. Here are some pics of my room, which I am quite proud of. I tried to turn all the lamps and everything on and shut the blinds so you can see how its lit, but I don't think it worked very well.

I got this small halogen lamp at Ikea for around $10 and put the dimmer switch on it. Also don't forget the minifridge full of your favorite beverages and a Wii and PS2 for when you feel like doing more than chilling and listening to music. The TV is also on a swinging arm thing so I can turn to watch it in bed, $25 at Ikea:
http://img.photobucket.com/albums/v304/bigk30/Bo063.jpg

I have another small light for my bed area, also from Ikea, but I found it in the garage of the house I am renting so I dunno how much it is. I'm sure its like $10-15. Also, 600 thread count Egyptian cotton sheets, a blanket that feels like a soft teddy bear, and a nice thick comforter from Target for when I'm ready to pass out.:
http://img.photobucket.com/albums/v304/bigk30/Bo064.jpg

This is my couch/desk area. My desk is a huge mess. I got the couch for like $100 from this sale at this furniture place my friend worked at. 100% leather and it reclines. The couch faces the TV with the PS2 and Wii.
http://img.photobucket.com/albums/v304/bigk30/Bo065.jpg

My room is really nice for chilling with 4-5 people. I love it. Hope this gave you a few ideas for your room. Peace.