Re: luxury invitations
^ that's one way of looking at it! lol
i believe that they're an important part of the "look and feel" you are trying to establish for your wedding. its not just a piece of paper, its YOUR piece of paper, you know? a wedding is beautiful because of well thought out details and design. anyone can throw 300 people into a banquet hall but what makes it different from a conference, is the detail you put into making it a special event for yourself and your guests, and invitations are the very first step in doing that. just my two cents :)
of course though, as with other wedding elements, you should go with what you love AND can afford.