We like wine! But also, wine increases the mood of any meal to one of happiness, and it is a mitzvah to increase our joy on Shabbat with fine foods and wines. The word Kiddush means to 'make holy'. By making a blessing for people over wine, we are increasing the special nature of Shabbat, and are adding a spiritual dimension to the meal we are about to eat.

Also, wine is one of the few physical things that improve over time. By using wine we are really saying that we want our lives to improve during the next week, just like this wine improved over the past week.

You can use any cup you like for your wine. Grape juice is perfectly fine as well if you're not a wine drinker.