I think you hit on it with "change" - it's not so much the materialism of getting new toys, it's the variety of new things, places, challenges, etc. I'm the same way, though it's rarely solved for more than a few days by buying something new. Seems to me that if you add variety to your life through meaningful methods (as mentioned above: spiritualism, music, knowledge, charity) you'll scratch the itch and enrich your life, as corny as that sounds...
