Since I'm always on the hunt for "house stuff" I really need to keep myself organized.
This is what I've found works best for me.
I bought a small, moleskin notebook with blank pages from an art store. I attach paint chips of each color I've used in my home, organized by room. I also attach any fabric swatches, wallpaper samples, or accent color's that I've used.
It's small enough to fit in my purse, so I've always got it with me.
There's also room in the back to keep track of measurements, for things like windows and furniture.
I don't believe in things being too "matchy matchy", but I do like knowing that the things I purchase will work in my home before I purchase them.