To Buy or Not to Buy?

You know how sometimes you want to buy something bad enough that you basically don't care about how much it costs? Well, my most recent object of want has been a XBox360. If you know mw, you're probably thinking something along the lines of, "Doesn't her brother already have one?" You'd be correct. He does have one, but I kind of want one of my own.
I have some good reasons, so don't accuse me of being an idiot just yet!
My brother's XBox360 is in his room, so there are times when he comes home and we, my dad and I, are in his room playing on it. I feel bad when it's late at night and my brother wants to go to bed but can't because I'm playing a game. Part of me wants turn off the game and let him sleep, but the other part wants to just scoot over so he can lay down and continue playing. My dad feels the same way I do, and has actually experienced more of these situations than I have because of the ever-growing stack of homework from school.
So, to solve this "dilemma," my dad and I have thought about buying our own XBox360. This way, we wouldn't bother my brother when we want to play more and he wants to sleep! Also, when my brother doesn't mind, one person can play on his XBox360 and be playing against whoever is on our XBox360! This would be especially cool for online, single-player games.

For a few days, we got to the point that we were about to go buy one. I still have the money that we put together with me in my room. Though, lately the urge to buy another has died off. So I don't know if we will buy one or not at this point, but oh well! :P