I agree chandellina, in my view wedding lists are tacky and vulgar. It puts the whole wedding invitation on a rather transactional basis (as one poster above put it "i'll spend £100 a head on feeding and watering you if you spend £100 on a gift for me").
Surely the point of a wedding is simply to ask your close family and friends to celebrate your joy with you? Anything other than that seems grotesque.
I have lost count of the number of friends of mine with whom I've been so disappointed on receiving their wedding invitation together with gift list - people I thought felt the same way as DH and me. DH always says, what towels/saucepans/sheets/cutlery/glasses did they use before they got married then? This urge to upgrade all one's possessions at one's friends' expense is simply greedy and just makes me regard those friends as show-offs.
Of course we never go empty-handed to a wedding, christening, dinner party etc - but given the choice we would always choose something thoughtful as a gift which means something to us and the host, not 3 towels and an egg whisk adding up to £100. And it would be a gift, not a payment for services rendered.
Disclaimer - My distaste for lists does not extend to refusing to use them if sent, after all it's about the couple not me, but I do think much less of people if they include a list with their invitations unless it is an Oxfam or other charity list.
And asking for money or vouchers instead is even more tacky.
IMHO the only circumstance in which it is appropriate to have a wedding list is if you are leaving your parents' homes for your own and genuinely setting up home for the first time after the wedding - in those circumstances you don't have bed linen, towels, toaster, kettle etc. But even then, the gift list ought only to be sent to people who request it.
(We did not have a wedding list when we married - as two independent adults we were combining two homes and it would have been ridiculous to ask for presents - in fact we asked people not to buy us gifts but simply to share the day with us. If people were desperate to spend money on us we suggested they consider donations to a charity we favoured. In the event many of our friends and family did bring gifts, all of which were very personal, and are now much treasured and frequently used even if slightly silly.)