HDTV (the hdtv is not as important as having movies or something interesting to watch)
blacklight fixture. (Long, celling mountable, one good blacklight is more 'pro' then a couple standard ones)
posters.(reflecting the two of your personal interests, go for comfort, not sterotypical)
Carpet (get the nice, but inexpensive roll out kind, people are going to be smoking in your room, so its bound to have a few drinks spilled on it)
Bud (its marijuana for smoking)

You can find a lot of stuff using froogle(dot)com it's something that google offers to help you find the best price of stuff online. But i'm willing to bet your local mart-wal has all of this stuff (Cept the bud) and a few other things you will want to pick up that you didn't think of. Congrats on you and your [partner] moving out of the cluthes of room mates. I'm headed for that road in a few months myself. Good luck to you, and let us know how your room turns out!