I live by the rule that flowers and gifts are not symbols of regret but should be symbols of affection and love. I will never use flowers as a way to say sorry. My words and subsequent actions should be enough without resorting to infantile bribery.
I don't see it as bribery personally. I see it more as a peace offering, and it works. The goal is to get out of the doghouse as quickly and efficiently as possible, so if you have to kiss some ass, say you're sorry, and spend a few bucks on her then DO IT. (lol)
Of course if you keep "slipping up" doing whatever bone headed thing that got you in the doghouse in the first place, i'm sure the flowers will wear thin.
The same sort of peace offering works with guys too. When a bud pisses you off, then shows up with a case of beer and says he's sorry, its hard not to forgive. Even if he doesn't say he's sorry, its hard not to drink his beer :)
Path (it always comes back to the beer)