I guess I can just keep my eye out for beautiful old stamps, but I suspect every other wedding blogger out there has already bought all of the non-cancelled ones by now, so I'm moving on.
Another source for pretty wedding postage stamps seems to be the custom design route. I've seen a lot of custom stamps that mirror the invitations really closely, but I think that tends to be design overkill. If I went this route, I'd definitely go with monogram stamps... maybe in complimentary colors between the invitation and the RSVP. I think it would be a nice, clean look that would match our invites better than the USPS stamps currently available...
What did you do to dress up your wedding invitations? Do you have any experience with custom stamps?