Lechatchila (a priori, by standard Halacha), can you make kiddush with grape juice or white wine? Can you fufill the mitzvah of drinking your 4 cups on Pesach with white wine or grape juice, bedieved (a posteriori, at a minimal level)?
Red is described as preferable, though white is always acceptable if necessary. (Or perhaps even if it's a type of wine you strongly prefer.) During times of the blood libels, white wine was actually recommended for the seder as no one could claim you were hiding blood in your glass.
For regular kiddush, the Gemara says you can use freshly-squeezed grapes. The question is with today's pasteurized grape juice. While there are some rabbis who feel it's Shehakol, the overwhelming majority opinion today is that grape juice can be used for kiddush. (Rabbi Zevulun Charlop has a YUTorah mp3 on several interesting shifts in thinking over a generation of rabbis; this is one of them.)
Grape juice for the 4 cups is a little bit shakier. Rabbi Heinemann feels that to demonstrate freedom, there should be some small percentage of alcohol that can still be tasted. His mentor Rav Moshe Feinstein also felt that grape juice wasn't acceptable, citing the Gemara about a rabbi who complained that the only time in the year he drank was the 4 cups on Passover, and that left him with a nasty headache for weeks. "If alcohol was so disagreeable to his body, why not just drink grape juice?", asked Rabbi Feinstein. "Must be that grape juice is not acceptable for the 4 cups." (Others retorted that grapes are harvested in the summertime; without modern technology, there was no way to obtain grape juice in the early spring. You had to ferment it into wine to preserve it.) Mind you, the Kedem grape juice says on the label that it's kosher for the 4 cups (with the blessing of the Tzelemer Rebbe, if I'm not mistaken), and many people use it, especially if they've hit their limit on alcohol.
But if faced with the choice between white wine and (purple) grape juice: white wine is very clearly suitable for kiddush and the 4 cups, merely less-preferred than red wine. Grape juice has some rabbis against it. So for the 4 cups, certainly white wine would be better. For kiddush, there's also the value of what you especially like, so if that happens to be grape juice, you could rely on that. But white wine is always safe, halachically.
During the era of prohibition (of alcohol) in the United States Rabbi Levi (Louis) Ginzberg paskened that grape juice was usable lechatchila in fulfilling mitzvot such as kiddush and the four cups on passover. A summary of his reasoning can be found here: http://www.schechter.edu/four-cups-of-wine-a-path-to-freedom/
We thus arrive at the following decisions: … From the point of view of Jewish law and custom, there is no preference to be given to fermented wine over unfermented. Both are of equal standing… As for the objection that has been raised against the use of unfermented wine for religious ceremonies on the grounds that it is against Jewish custom… There can be no doubt that in the past most of the wine used for religious purposes was fermented, since the process of preventing fermentation was unknown. But to base on such a fact the prohibition of the use of unfermented wine would be as unreasonable as to suppose that because only wax and tallow candles were used for lighting synagogues, the use of gas and electricity for that purpose is forbidden. (The Responsa of Professor Louis Ginzberg, ed. D. Golinkin, New York and Jerusalem 1996, pp. 130-131).
Other orthodox Rabbis responded to R' Ginzberg's psak years later. A summary of their rebuttals can be found here: http://americanjewisharchives.org/publications/journal/PDF/1991_43_02_00_sprecher.pdf
By and in large the reasoning of R' Ginzberg has prevailed to this day. Additional sources can be found here http://www.torahlab.org/doitright/using_grape_juice_for_kiddush/ and can be summarized as follows
The common practice, and the position of the vast majority of contemporary poskim including Rav Moshe Feinstein, Rav Elyashiv, Rav Ovadia Yosef, Rav Soloveitchik, and the aforementioned poskim, is that grape juice may be used for Kiddush and all other sacramental purposes. Many do note the position of the Magen Avraham, that it is preferred to use wine when possible.
Orech Chaim 272:4 says that Ramban disqualifies white wine for night kiddush even bidieved.