White Dress, White Flowers?

Unless you are allergic or something, I think you should use real flowers for you and your bridesmaids bouquets.  I would use less expensive flowers etc.    You probably could use silk fllowers in the centerpieces and decor to save money. 

As for the color white, I really wouldn''t worry about it perfectly matching. 

Nope! I don''t think they need to match perfectly.  I think having them slightly off will help your flowers stand out.

If they match perfectly you won''t be able to really see them.

And yeah, I agree that by the time you spend the money on really good silk flowers, you''re better off using real ones.

sum brings up a good point about the contrast. i thought all along i wanted off-white roses to go with my dress, which was lace and i was afraid of having the flowers be too busy against the dress. my florist and photographer both piped in that the flowers would be ''lost'' in photos against the dress unless there was some contrast.
i ended up keeping it simple in terms of one color, but went with all dark red that really popped in the photos, without competing with my gown.