I've got all the houses but it's just a pain. I can never remember where i've put things.
Solitude was the biggest waste of coin, in my opinion anyway.
I have the same problem. I have all the houses, but I can't ever remember where I put stuff...even my wife. I married Camilla Valerius, the woman from the Golden Claw quest line. She is pretty awesome because when I get home, before I drop stuff into storage, I can sell items to her. On top of that, she has a dialogue option where you get a share of what her store has made. Well, anyways, I had most of my stuff in Breezehome, the house in Whiterun, and I went there to drop stuff off, and she wasn't there. I was pretty puzzled. I walked all over the house and she wasn't there. So I walked around town to see if by chance she ventured outside, nope. So after i did all that I needed to do, I went to my home in Solitude to get something and there sat my wife....I completely forgot that i told her to move...felt like a total doofus....