I just saw the most simple/chic/clever Save the Dates (STDs ~ I know, horrible acronym, but you'll get used to it) over on Invited Ink's Etsy shop.
Not only are they antique handmade letterpress - so posh! - but they are so clever! Invited Ink will personalize the name and location information on the STD card, but YOU punch out the Month, Date & Year of your wedding using a standard hole punch (or whatever punch you desire).
The best part: Even if you didn't have your wedding date settled on, you could still order these ahead of time! And believe me, you want to get done as much as you can ahead of time.