I'm the same way, it's that oldschool game treasure hunting mentality, it's tough to shake. Anyway, I can say that while in the base game I can't think of anything that was extraordinary in a random NPC house. As mentioned above, I can say I have never needed to craft or purchase Dwarven spirit or strong alcohol needed to replenish stocks after meditating. Also, you do come across some places that have a number of furs that can land some decent coin at the right merchants.
Now, I just started the first DLC (Hearts of Stone) and it's a whole different ball game for random treasure hunting in the areas that are newly created on the map. I find awesome weapons and armor all over the place. While this isn't so much in people's homes, it definitely is if you go off the path a little. Particularly, a light house in the far northwest corner above Novigrad, there are some random people living there and I almost didn't go in. I'm glad I did, because the all black New Moon armor is sweet and way better than what is provided during the story.