For our Save-The-Dates, we're going to send a postcard (in an envelope) to our guests.  The front of the postcard will have the Kerne Erickson (one of our favorite artists) "Palm Beach" print on the front (pictured below), with the information and one of our engagement pics on the back.  This print looks very similar to our reception venue, so we lucked out :)  
 

Here are what our invites will look like! My planner has an invite girl who can make them at a much lower cost than if I got them through Vera Wang (we love her Aquamarine invites).  The envelope liner will be coral instead of white.

I love this idea, and will definitely be making something like this by myself for the bridal party.