MLibbyDP:

Now, see, Mermaid, we have it on good authority that Emily Post's Etiquette merely requires a NOTE of well wish in response to a wedding invitation, not an actual gift....

Really? My good authority is Emily Post herself:

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Please read #3. For all of you that can't pull the link, it states:

If you are invited to the ceremony and/or reception, you should send a gift, whether you are attending or not. Generally, gifts are sent to the bride in advance of the wedding. In some localities, gifts are brought to the reception and placed on a special table. If you hear from family that the couple would prefer a charitable donation—as in the case of an older couple or an encore wedding —please respect their wishes. If you receive an announcement after the wedding has taken place, you may send a gift if you wish, but you have no obligation to do so. It is nice to acknowledge the announcement with a card or a note expressing your best wishes."

#3 is preceded by #1, which is RSVP, and #2 which is "respect your invitation" which means don't bring anyone not specified on the invitation, random SO, random kids, etc.

I'll happily accept any evidence to the contrary, but this has always been my understanding.

StationC, I do understand where you're coming from, however the thought on this is that the wedding couple is only inviting the people closest to them (hopefully) and that those close friends will want to commemorate the occasion by giving them a gift. Wedding gifts started out as a way for the couple to furnish their home, and it has morphed into a means of "commemorating the day". It needn't be an expensive gift, nor anything from their registry, just something personal to the couple. A picture frame, a small crystal vase, anything that every time they look at it or use it, they think "StationC gave us that for our wedding..." It's for this reason that I prefer to give them something lasting, not a set of towels or any other mundane household item, even if it's on their registry.

One of my favorite gifts to give for weddings (or bridal showers) is Emily Post's Etiquette (the newest version of which has been rewritten and updated by Peggy Post.) Anyone I've ever given it to has found it very helpful.