When we said that we didn't want anything - cash or gifts - I was surprised at the number of people who were quite put out.
You'd be amazed at the number of people who want to get you something to mark your special day. You'd also be amazed by the amount of people who do get you some horrible pie dish or vase a gift regardless.
Eventually we agreed that we wanted people who wanted to give us something to donate to charity instead.
Our wedding invitation said something like :
"We've been living together for a long time and already have all the toasters and towels we need. The best gift you could gift us is simply by being there.
If, however, you really want to get us something we have set up a fund in our new Mr& Mrs X name at SOS Children's Villages. It would be a very special start to married life for us if you were able to donate to this very worthy charity in our name."
I think the charity got several thousand pounds from us getting hitched, which was really nice.
We still got a few unwanted and pointless picture frames etc presents from people who just couldn't get their head round not buying something, but on the whole it worked really well.
Alternatively - how about asking for honeymoon vouchers?
Someone I know had this recently and it was rather nice as it felt less impersonal and cold-hard-cash than John Lewis vouchers, and you could see what they were planning to do and how you were contributing.
We got a lovely thank you card on their return with a picture of them on a mountain lift thing which they said that our contribution had got for them.