LOL, I'm responding to a 3-year-old post...
Originally posted by Lord Lucien
Strongest raw power: Palpatine. The kind of sheer energy needed to create the Force Storm, and to fine-tune to a teleporter is amazing. Marek's got nothin'.
Although Palpatine's Form storms stand as perhaps the most impressive feats in the mythos, one must remember that the fact that Palpatine needed to develop an entirely new Force ability indicates that he cannot replicate the feat using mere telekinesis or lightning. So it's dubious as to whether his "raw power" exceeds that of, say, Luke or Kyp, who manipulate dorvin basals with raw telekinesis.
Nihilus' raising a fleet out of a gravity well is a second, I'd say. Though, again, not enough details.
IIRC, don't we only know this through pathological-liar Traya?
For all we know, he just used tractor beams.
The ancient sith's feats are apocryphal like that.
Strongest potential: Anakin. Lucas has made that clear.
Luke insinuates, and Kyp even claims in NJO, that Durron has more potential than Luke Skywalker...but it looks like that's been retconned.
Strongest Potential realized: Technically, the dustmite that reaches its full potential is strongest. This one's too ambiguous.
I think the OP's referring to the most powerful any Force user actually became, so I suppose "potential" was simply faulty wording.
...or not, given the "strongest overall" category.
I'd point to Luke, Palpatine, Yoda and the [which you didn't know existed] Sith Emperor.
------
I'd add in the categories "most prodigious learner" and "widest Force knowledge", and nominate Luke Skywalker for the former, and Odan Urr, Vitiate, Palpatine and Yoda for the latter.