Especially when I see gorgeous cards like the ones above, found on the Kate Spade website. They're engraved, on heavy stock and are blank inside, perfect for a little note. Also, they're only $25 per box of 15, which, in the grand scheme of things, would hardly add anything to the cost of party planning.
Maybe that should be my second-half-of-the-year resolution: send more invitations. That's a resolution I bet I could even keep.