@erika1016: So, since this is the etiquette board, I am going to give you what proper etiquette says, with reasons and background, and then you can use that as part of your palette to make your own decisions.
Three basic principles of etiquette are:
1) Form follows function. Things like invitations serve a purpose. They should be designed to serve that purpose well, whatever else they may do.
2) Less is more. Sparseness carries a degree of elegance and good taste. There is no point in hanging on useless bells and whistles, and extraneous phrasology unless they serve a purpose.
3) Consistency is next to godliness: Be formal, or informal; be traditional or off-beat, be tactful or candid; but don’t send your guests mixed messages and leave them wondering whether they should come wearing formal jewels with loafers.
A proper invitation tells the recipient overtly WHO is hosting, WHOM they are inviting, to WHAT, WHERE and WHEN. It tells the recipient covertly, by its form, about the degree of formality to be expected. Formal invitations use stilted third-person wording and follow a standard pattern. The more rigourously they conform to the standard pattern (and standard materials, to whit black ink either engraved or hand-written on heavy white paper), the more formal the party they are advertising. Informal invitations use natural wording and follow the pattern of a short note.
The “host” of an event is not the person who pays for it (polite society does not talk about cash and finances, those things are kept private), but the person who takes personal responsibility for the comfort and well-being and entertainment of the guests; and who therefore has responsibility for the final say on anything that might affect the guests, including the final say on the guestlist itself. For a wedding at a church, that person is “God” (or god’s spokesman the minister), not you, so you cannot “request the pleasure of their company.” You can however let them know that you would be honoured if they were to choose to exercise their pre-existing right to be present. The same is arguably true of court-houses, where the Judge is the “host” and where most marriage acts require that the room where the marriage is performed be open to the public. At private homes or rented venues, the lady organizing the event is the hostess, and if she is married her spouse may be named as co-host. Most properly, only one lady is named as hostess (so that there actually is someone who can say “the buck stops here!”, there being no co-hostesses to whom she can pass the buck, and no-one with whom she can find herself in a deadlock over details like chair covers and centrepieces.
So. You are the hostess. You are named complete with your surname because the invitation is being mailed to people who might know more than one “erika”. You give your future intended a surname, because ditto. Your guests get title and surname only if you are being formal, because they are pretty sure who they are already and don’t need the extra names to be sure. If you are being informal, you use their given names only, without titles. So the most proper invitations would read:
(for a formal wedding)
Ms Erika Teuton
requests the pleasure of the company of
(blank line here to write in guests’ names, e.g. “Mr Smith and Ms Jones“)
at her wedding to
Mr John Thomas Brown
on Saturday the fourth of January
at eleven o’clock
at Legion Branch Twelve
and afterwards to dinner and dancing
at Victoria Park Golf and Country Club
at seven o’clock
(or for an informal wedding)
Dear Anne and George,
I am so happy to tell you that I will be getting married to John next January, on Saturday the fourth of July. The ceremony will be at eleven o’clock at Legion Branch 12 at eleven o’clock; and we’ll be celebrating with a dinner dance at the Victoria Park Golf and Country Club afterward beginning at seven o’clock. John and I hope you will be able to attend;