When one recites the Beracha of "Boreh Peri Ha’gefen" over wine, this Beracha covers all beverages that he intended to drink at that point. Thus, for example, when a person attends a Kiddush, the Beracha he recites over the Kiddush wine covers all the juice, water, beer, scotch and other beverages that he drinks at the Kiddush. Even if a person hears Kiddush and drinks only a small sip of wine, the Beracha over wine that he heard covers all beverages that he had in mind to drink at the Kiddush.
However, Rabbi Moshe Halevi (Israel, 1961-2001), in his work Birkat Hashem (vol. 3, 10:85), imposes a very significant limitation on this Halacha. In his view, the Beracha recited over wine covers the other beverages only so long as a person still intends to drink wine. Since he plans to drink more wine, the Beracha that he recited is still relevant and thus has the capacity to cover all other beverages. Once, however, a person decides not to drink more wine, he must then recite Berachot over the other beverages he drinks. This occurs very commonly at a Kiddush. Many people take only a small sip of wine to fulfill the requirement of Kiddush, and have no intention of drinking any more wine. According to Rabbi Moshe Halevi, they would be required to recite the Beracha over the juice, water or other beverage that they drink at the Kiddush.
Hacham Ovadia Yosef, however, and his son, Hacham David, disagree with this ruling. As Hacham David writes in his Oserot Yosef (vol. 9, Siman 1; listen to audio recording for precise citation), the Beracha over wine covers all beverages that one intended to drink even after he has decided not to drink more wine. He explains that when a person recites the Beracha of "Boreh Peri Ha’gefen" over wine, he is considered as having recited the Beracha over all beverages he intended to drink at that point. Accordingly, he is not required to recite a Beracha over other beverages regardless of whether he plans on drinking more wine. For all intents and purposes, he has already recited the Beracha over other beverages, and he therefore has no reason to recite another Beracha, even after he has decided not to drink more wine. Hacham David notes that this is also the position taken by some earlier authorities, including the Kaf Ha’haim and Mishna Berura.
Summary: The Beracha recited over wine covers all beverages that a person planned to drink at the time he recited the Beracha. This applies even if he drank only a small sip of wine, and even if he does not plan on drinking any more wine after his initial sip.