Which speaker is better

Haven't heard the SE25, but did have the opportunity to audition the new Dynaudio 1.4 against the B&W 805 signatures. Power provided by Cary amp and pre (can't remember model #'s) and source was top of the line Cary player. For my taste, I felt the 1.4 was a better match for the Cary; though both were good. It seemed the B&W had a tad more bass extension, the dyn had smoother highs. Overall, I felt the dyn was more musically satisfying, but again, just my personal taste in sound. I seem to prefer those soft tweeters! Try to audtion them side by side, with the same setup.

i have listened to the sonus faber and just recently to the se 25 dynaudio at he2003. both are very nice speakers. they are both much more musical than the b&w's. i would look into/audition the speakers from totem. i have a couple pairs of their speakers currently and i think the speakers vince (owner of totem) had in the totem room at he2003 (hawk and forest speakers) sounded better than either the dynaudio se25 or the sonus faber at a much more reasonable cost. even if the totem were the same price, i would prefer them over the others. (imo)

Different speakers different character. Its all up to your taste.

Sonus Faber - when you need more on musicical feel and romantic air, dont mind resolution. It is audio gear friendly brand. You can have good sound applying wide range of audio brands.
B&W - If accuracy is more important, and you dont mind it is a but pricy
Dyna - Very good in high and mid, you need to be careful in amp selection as it truly reflects the performance of your system.

my view.

I second Rbstehno's comments. I used to own B&W and find them not musical enough. Of your list, SF would be my pick but again this all depends on your other components.
However, for the money, you should seriously audition the Totem speakers. The value is unbeatable.