Actually the berries that most people would consider "best" are not obtained from the Berry Master... they are obtained from his wife. Tell her the following phrases (one per day) to get a rare berry:
CHALLENGE CONTEST (must have Contest Pass, I think)
SUPER HUSTLE
COOL LATIOS (must have seen Latios)
OVERWHELMING LATIAS (must have seen Latias)
For these and all other rare berries, 2 is the most that you can grow, and they take 72 hours to harvest. In order to get 2, however, you have to water them several times a day. If you don't have the Wailmer Pail to water berries with, you can get it from the flower shop between Petalburg Woods and Rustboro City. There is no specific place that is best for raising berries, but some places you might find useful are the Berry Master's garden and the 2 patches near Mauville (one south of it, one west of it).
As far as what Pokémon I used to win the contests, I used Milotic for Beauty, Electrode for Cool, Regirock for Tough, Whiscash for Cute, and Dusclops for Smart.