As a society, we've gotten away from formal correspondence - we have so many very convenient communications options that calling cards and expensively produced invitations to dinner don't just seem old-fashioned, they seem ridiculous.
Even though I'm not an evite fan, I mostly get why correspondence has evolved. Really, I do. But in some cases, I think we ought to make the effort to bring some of the old school back. The fancy dinner party, even when it's just with your friends, is one such case.
For instruction on how to invite friends or acquaintances to a dinner party, I turned to one of the grandes dames of etiquette, Emily Post. In her book, Etiquette (published in 1922 and helpfully reproduced on Bartleby.com), Post explains everything anyone would need to know about the wording and structure of formal invitations.
She states that invitations should be engraved and she indicates that, for the most part, flourishes aren't welcome. Straight text, simply stated, is best. For the busy entertainer, she recommends having a set of fill-in cards produced. Something simple and clean, like this Vera Wang card:
This card makes it easy to fill in the name of the people being invited, as well as the location, date and time of the event. Those can all be handwritten.
Is it a little affected, if you're a regular girl (or guy) living in regular America? Sure. And is it expensive? Oh hell yes, especially if you go the proper engraved route. But is it the kind of throwback nicety that would bring a smile to the face of nearly every recipient (especially if that recipient is your grandmother)? It really is.