The first thing you'll notice about wedding invitations is there is A LOT of crap to them. Return envelopes, RSVP cards, tissue paper. I read an eHow on what order you were supposed to put everything in the envelope (very important was the tissue paper placement).
I did not want these fancy envelopes. For one, they are expensive. I'm talking way out of what I could ever justify paying for a piece of paper with a time and date on it. Also, I believe stuffing envelopes is something that should be left to scams and pyramid schemes. Third, I don't like fancy script and I don't like things that drag out saying what we're all waiting for. By this point, you've received a save the date, if we're Facebook friends you've seen the photo album. You know what's coming... you don't need: "With their parents ______ and ______ would be honored at your attendance honoring their love and yada yada yada..." You just need to know who and what. And heavy wording and a fancy script really would raise the expectations far too high for this party. I can't send out a purple and silver stuffed engraved invitation (with tissue paper - I'm really hung up on this tissue paper nonsense) and then serve everyone burritos and rock candy while they listen to karaoke.
Now, as I might of mentioned before (I really can't remember) when you register at Target they give you a little carrying case and a $20 Shutterfly gift card. We had long decided before we got the gift card that we'd probably print our own invitations but still the prices at Walgreens and Kinkos were a little more than we expected. Not only did Shutterfly end up having the lowest rate but we also had a gift card. We ended up with 125 custom made invite cards (and envelopes) for about 40 dollars.

Since these were cards (and basically just say the names and place) we added little inserts that tell everyone to RSVP to our wedding e-mail and also have a link to our The Knot website.
Of course, two days after sending them out someone tells me they say "RVSP" which I've just decided means "respond very soon please!"
We thought the photo-heavy personally designed invites would be nice for far away family who like to have pictures and would be nice for people who couldn't make it to at least see who their friend or relative is marrying.
Finished result:

I thought of blacking out the date and time, but I figured if anyone who happens across this and isn't already invited shows up... my security will handle it.
Also, the great thing about the e-mail RSVP system is that Gmail lets you create labels (they're sort of like folders, but less politically correct) so now when I get an e-mail, I can read it and then sift it easily into the "Attending" or "Not Attending" folder. It also means that when someone sends a heartfelt apology and wishes us well I can respond back immediately. This also leaves me with an inbox full of "best wishes" and "congratulations" to easily look back on.