Having a small home in an urban area is my cure for clutter and my recipe for quality of life. Here in the NYC metro area, space is at a premium. Its just not possible to accumulate that much stuff unless you want to "wade" through it. We have a 2 bedroom 2.5 bath duplex with about 1700 sq ft and its pretty huge by local standards. Urban lot, so no yard = no yard work and no lawn care equipment
. Very easy to live without a car if you want. Grocery store, restaurants, bars, pharmacies, hardware store, even a full fledged mall are within walking distance. If you can't find it in walking distance, 24hr train service to Manhattan is 500ft away.
We still have to work at managing our stuff though - its just that we don't have room to accumulate for years and years. My wife cleans out the closet every 6 months. Any piece of clothing that hasn't seen the light of day in 12months goes to the Salvation Army. She also buys used books there. You can get a stack of paperbacks for $0.25 a piece. The rule is she has to drop off books that we've already consumed before bringing any more home. I've found that the craigslist "free" classifieds is a great place to get rid of old stuff you don't want. I got rid of an old desktop computer I wasn't using any more. It didn't work (harddrive was toast), but someone who was low on cash was happy to take it away and give it a new life. I did the same with a washer dryer that crapped out, and an old espresso machine. We can also just drag old crap we don't want to the curb and it nearly always gets taken by someone.