I *love* having my boys share a room. It's still working really well, even thought my older son is 12 and his little bro is 9. Every night I tuck them in, then lie with them for 1/2 hour, 45 minutes or so; and what wonderful laughing fits and conversations we have! (After school, if I ask them how their day was, it's just "fine." in a monotone). All of a sudden, at bedtime, with all three of us in the dark room, the floodgates open!
I hear all their funny ideas, concerns, worries, etc; and I'm able to talk to them about any issues that they're worried about.
And when I say goodnight, they lie there giggling and making jokes (usually about butts and farts, even at this age!) until I call to them to go to sleep.
I know my 12 yr. old is going to want his own space soon. But I am firmly dedicated to the idea of keeping them together as long as possible. It makes for a more intimate and fun bedtime for them. And that's about all the time they spend it their room! If they didn't sleep in the same room, I don't think they'd be as close.
If we ever can move into a place with enough bedrooms, I guess I'll have my oldest ds in his own room as a teen, and put my second ds in with his little baby brother, who's 7 years younger. I really think it helps them developmentally, to have this intimacy with their siblings. Heck, most of the world's population sleeps together in one room with the entire family! Look on the Simple Living forum for more on simplifying in ways that make your life more meaningful!
Oh, about their stuff. We keep big stuff in the garage, little stuff in baskets in the living room (which is also the playroom and looks like one), and their school things and clothes and books in their room.