You should totally go to a place like a Thrift Shop that sells furniture, and just buy like a cheap love seat, and a cheap recliner. Having places to sit is a must. A nice television/sound system is a must, all the stuff that you have is good. Also, I would get some incense just because it rocks, and video games, and some of those posters that react to blacklights, and black lights....

Hmm, that's all that I can think of.