I can't help much with the furniture and things, but I do know that if you eventually have a stash of any size, you're not going to have enough room for long, and a long arm definitely won't fit. My old sewing room was 20x20, I sure do miss it, because my "new" sewing room is 9x15. Once we get the GD through college, we'll build a bigger home with a large enough sewing room, but that's at least 4 years away.
Congratulations on the purchase of your new home.