rob and Sam2,
On the surface this appears to be a stirah. On the one hand the gemara says that one should praise the kallah (in the presence of the chosson) for her beauty and on the other hand it assurs histaklus.
I think that the answer is fairly poshut.
What the gemara is assuring is gazing at the kallah to give the impression to the chosson that you are attracted to her beauty. This the gemara says is forbidden (presumably because it gets too close to histaklus for hanah). On the other hand, it is muttar to look in a quick fashion at the kallah to be able to praise her beauty in words to the chosson.