I'm sure you will look fantastic no matter what you wear!
I'd like to suggest something a bit different. I've shot literally hundreds of engagement pictures - Here's two things to think about -
#1 - Remember that you two are in love. If you can, forget about the camera for a few moments, and just try to be in the moment with your fiancee. Have him hold you close, snuggle, enjoy each other, and just be!
#2 - Look for spots with "open Shade" Avoid direct sunlight. Instead look for a big shady area near the side of a building (don't get right up next to the wall all the time), or under an awning. Also avoid spotty shade, like under a tree, where there are lots of light and dark patches that can make your face and clothes look mottled.
Have fun, and be sure to post a link here when you are all done!