Well, here's the thing though - for some of us, the presence IS what matters. I wouldn't put it on a wedding website or, heaven forbid, in an actual invitation, but I don't think it's smug. In some cases it's just what's true and it doesn't make those of us who feel that way better or worse than anyone else. At this stage in my life, my friends are all insanely busy so the only thing I want for my wedding is for them to make what I know is a sacrifice to spend a few hours with us.
I didn't put this very well, did I? Of course their presence is what matters to you! My point is just that when people say so explicitly, it implies that it is NOT what matters to others, or at least that it matters less to others. That's the part that feels vaguely self-congratulatory to me. I've seen posters on eHell saying suggesting wording like "We value people more than possessions, so no gifts, please" -- much more extreme, to the point of real preening, but maybe helpful in illustrating the point. And I suppose that some people could take "we already have everything we need" to be bragging or at least insensitive to those who don't. I don't mind "no gifts, please," and leaving it at that. There really isn't any need to state a reason.
Toots, this is a rare instance in which we disagree, although actually only partly. I do agree with your points. But the way I see it playing out is that the incipient recipient
says "your favorite charity," which means "any charity, we're not designating a specific one unless you ask us," and then the guests either ask them or someone close to them, or choose one they are confident they will like.
What I was trying to find wording for was the thought "We are already so blessed, and charities, including your favorite, need your generosity more than we do, so that's what would please us most." But talk about sounding smug and self-congratulatory!
Maybe you could write, "What we would appreciate most is a gift in our honor to the XYZ Fund or to your favorite charity." or "What we would appreciate most is a gift to your favorite charity or to ours, the XYZ Fund."
For a wedding I would choose a cause that helps the needy (for a birthday I might pick arts, animals, environment, public radio, or whatever they love best). Probably that is a relic of the Jewish custom of feeding the poor when you are giving a feast -- usually done these days by a contribution by the hosts and/or guests of honor of an amount equal to some percentage of the catering costs to an anti-hunger organization or food bank. So I guess that's why I see it as an apt choice for a guest, too, just extending the idea of sharing good fortune at a time of celebration with those not so lucky.