What are the major rabbinic opinions today concerning the suitability of substituting another beverage for wine (or grape juice) for kiddush and other "cups of blessing," e.g., havdalah or Passover seder's four cups? Can one use another beverage even if wine is available? If one finds something distasteful, does that disqualify it from use?
Friday night -- either wine, or challah.
Shabbos morning kiddush, as well as havdalah -- better with wine. Acceptable with any "beverage of the land." (How do you balance "better" vs. "acceptable"? AYLOR.) Beer definitely works as "beverage of the land." Hard liquor -- there's a discussion about how much you'd have to drink. Rabbi Ovadiah Yosef quotes some sephardic opinions that the beverage must be fermentable -- I assume apple juice would still count? Otherwise (at least for Ashkenazim) I've generally heard coffee, tea, milk, apple juice, orange juice. Many poskim allow soda (though the diet versions might be pushing it); Rav Moshe Feinstein didn't. "But they serve it at all the fancy weddings!", someone asked him. "Still no", he replied.