This was my first thread posted as a member, and have to say I'm very impressed with the helpfulness of everyone! Thank you, and thank you all for the congratulations!
If you're interested in my decision, I changed to worsted. The only less traditional (as far as I know; maybe it's more traditional?) part is that I had the vest made completely with the wool, and no lining on the back. I wanted something nice and formal that represents my respect for the day and my fiance, something that is more timeless and I could wear over and over again, and to get a closer compliment to her dress fabric (though i haven't seen it, it's supposedly more of a smooth look than a matte feel/look).
If you're still interested in more details, I was thinking these Allen Edmonds: () in the burnished brown, and an eggplant purple tie (it's one of our colors).