"I absolutely do not want more stuff. Actually, we're gonna have a box of crap that we want you to take stuff from so we get rid of it."

It's so nice to get older and have friends like that. :-)

Edit: I know this seems trollish, but it's probably also true. Although I could have worded it better, my point is that your expectation that people _not_ give physical gifts is no different or more noble than other peoples' expectation that you accept physical gifts. Recognizing that, there's the tried and truism that it's easier to change things about yourself than things about others.