Since you have no job and no money, I suggest you take it slowly. I'm 16 and CURRENTLY have no job (had one a while ago). I have 300$-ish from my birthday and the money I got from my job which I didn't put into school savings. My brother has a bit more than me since he returned his ps2 at costco a month ago and got the 400$ back. Me and him are splitting the costs for the 360.
I will have no money after that, except for 150$ credit at ebgames and whatever I get when christmas comes around the corner. I'm looking for a job now, but that doesn't matter right now.
I will get the VGA adapter and play on my 15" monitor in my room. It does 1280x1024 (don't ask me how a 15" crt monitor does 1280x1024), so I can play Xbox 360 in 720p withnthe vga hookups.
I'm not gonna waste all my money on a bigger screen right now because, first of all, I'm only fugging 16. I'm not gonna go spend loads on surround sound because I'm fugging 16. I'm not gonna sacrafice everything else money can buy (school, gifts, games, trips to the movies, etc) to get a 'better' gaming experience. I know my limits as of now and I'm not gonna pretend I'm a 25-35 year old man with money to spare. Sure, many of the guys around us have monster HomeTheatre setups, but they are older than us and have a job etc. We can't feel like crap for having a crappy setup compared to them - we should have a crappy setup compared to them.
Don't get ahead of yourself. Someday you will get all that HT goodness, but right now we just can't afford it. No one expects us to have the bells and whistles, and you shouldn't either. If you did have the cash to spare, then I'd say go for it, but since you obviously don't, just wait it out and enjoy the next gen the best you can. There's nothing to be ashamed of.