[Keeper of Dol Guldur]

Galadriel was wisest, that doesn't make her to most powerful elf in Middle-Earth. I already said Celeborn was, certainly. But as for the comparison between Elrond and his 'mother-in-law', the argument is perplexing. The elven rings together with the bearers, would put them on equal ground if Galadriel was the more powerful, as Elrond had a stronger ring. But I don't think they make much of a difference. It was said in the "Slayer's Chronicles" series, the first rule of nature is that "hybrids are always stronger". Elrond was a hybrid, Galadriel was not. He shared the best traits of both the races of men and elves (and had a little help from his 1/16 Maiar), but he was completely elf and not half-elven, because he chose to be an elf, and live forever. As for Galadriel, she had seen the light of Valinor, and was counted among the high-and-mighty of the elves in the blessed realm even before the quest for the Silmarils. It's still sketchy, I can see where it would point to Galadriel, but it still (trait-wise) depends on one's definition of power. Wisdom, both had.