Poems are terrible.
Rule that out right away.
We faced the same dilemma in as much as we definitely didn't want physical gifts, as we live abroad, so it would be a logistical nightmare trying to get any gifts back with us. At the same time, we will be setting up a more permanent home in a different country in the near future, so it would be nice to have some money to do that further down the line.
Since we are both totally awkward, we just didn't mention anything about gifts whatsoever on the invitation.
For my partner's side of the family we set up a website with information on logistics, hotels, etc, and had a section on gifts which basically said "we absolutely do not expect gifts from our guests, but if you would like to give us something, then we would be grateful for any cheques or vouchers to put towards our honeymoon or to set up our future home".
On my side of the family, I am guessing people just asked my parents, who were probably a bit less tactful.
I disagree it's a generational thing though - neither of my parents could understand why we would have any embarrassment whatsoever asking for money over gifts, as that has been the norm for every wedding they have been to in the last 20 years. One of my partner's uncles actively recommended that we ask for contributions for our honeymoon, and said that they did exactly the same thing a good 25 years ago.
My view is this: We don't expect people to give us gifts. They are not "funding" our wedding in any way, shape or form. If they genuinely want to give us a gift, then they will be happy to give us whatever we would find the most useful. If they aren't happy to do that, then they are only buying something due to convention, not for our happiness, in which case they just shouldn't get us anything. And we aren't going to think any less of them for doing so.
I think it's actually parents who might get a bit more irritated - if they have given cheques for X amount for a number of weddings for nieces and nephews or whatever, then your child gets nothing at their wedding, I can see how that would grate. Family politics eh.