We decided to save money by combining our Christmas Cards with the Save-the-Dates (aka STD). We also sent out 'normal' non-STD Christmas cards to those that we were not going to invite). This saved us time (not having to design a specific "STD") and money (we're only sending out one card and not two, only need one set of postage for each guest/family). Plus, because we send out Christmas cards anyway, this item doesn't get budgeted into the wedding!
If you're having a summer wedding, consider sending out the STDs at Christmas! We ordered ours from Shutterfly with a coupon code.
It reads: "We are excited to inform you that we are engaged to be married.
July xx, 2010 ~ Invitation to follow"
We also included some pictures from our trips from the past year so those that may not have met one of us will get a visual of our significant other, as well as our wedding website.