I like the modern invitation you showed me, and we definitely could do something like that. It's simple and clean-cut. I like both, but it was a little "whispy" for me. I'm more of a bold guy, personally. (See #8 for something that incorporated both?) Here is my contribution.

(you should definitely "open in new tab" this one. Sorry about the periods; I couldn't figure out how to space it all out!)
.
I quick did a run-through of a google image search and found some invitations that I liked. I'm not much of a cursive sort of person -as you might be- but I'm definitely willing to compromise on that one. Here is a quick synopsis of what I like about each one:
.
1.) I like the basic geometric shapes and stark contrasting colors. It's a little too generic for me, but I'm usually pretty attracted to the strong use of verical lines.
.
2.) I really like the photo in this one. I know you didn't want a photo, but this isn't so much of a photo as it is an icon or symbol. I also really dig the white and light blue on the brown recycled-looking paper and the Sunday school envelope type rope thing tying it together.
.
3.) Not sure what I liked about this one. Aestetically pleasing?
.
4.) Simple two-color with a creative use of the word "do."
.
5.) I dig the clean, modern look and the simple bird illustrations.
.
6.) This is almost too bare-bones for me, but I threw it up there for a reason.
.
7.) If I had to have a design, I'd like something like the flowers: elaborately done in two colors that dominate the upperhalf of the invitation. I don't know that I'd like that concept with all illustrations, but the flowers just really resonated with me.
.
8.) I like a lot of stuff about this one. In paticular: the awesome calander thing they used, the use of bold "Impact" font and cursive and the colors. One of my favorites of the bunch.
.
9.) Birds again, but I liked the simplicity of it once again. And it was on black.
.
10.) This is very much my style (not as much as 12, but close!). I think it looks formal and classy and not very much like a birthday invitation at all. Unlike 6, the bare-bones really works for it. I really enjoy the variety in the fonts; it's not too random, but isn't repetative to the point of boredom.
.
11.) This is my favorite idea of the night: what if we made our invitations into CD holders that featured our favorite songs? That's something we have in common: we've both made CDs for each other and we both enjoy a variety of music (but have a few songs in common).
.
12.) Is the invitation that came along with the CD. It's a tad bit retro, but I felt that worked for it. We could incoporate different colors and a jazz theme, but it's not as formal looking. Maybe not even very classy?
.
13.) This is just a picture of the kit and kaboodle that came with the CD and invitation.
.
There you go. Love,
---CJ