My favourite is a tough question, I have so many...but...One of my prefered is Jacen Solo who have been the most jedi involved in the force than none jedi have been in the past. (From the Yuuzhan wong saga (books)) Naga sadow, exar khun, adjunta pal, etc... were very mighty, but Jacen is the only slave that survived to the Yuuzhan wong and see them thru the force !
Another if you allow me is Jaina Solo, his sister who have the renown to be the reincarnation of Yun harla the godess of deception and make numerous ravages in the Yuuzhang wong ranks with her x-wing squadron composed exclusively of...jedis, even defying the yammosks, (war coordinator, a special creature raised by the wong to coordinate an entire battle) So much to say about this saga, just a Yuuzhan wong quote : the translation in their language of surrendering = "obligation of the conquered to the conqueror", which means that either you're a slave, either you die, there is no other option.
The new republic is crushed in a short time, Corruscant falls, no one resists the wongs, not even the jedis (wong organic technology is too mighty)... except those like Jacen and Jaina who develop new perceptions in the force and special tactics to beat them. Does anybody have also read this saga ?

Darth Marr from KOTOR. He is a very powerful Sith but his judgment isn't clouded buy the dark side. He still thinks with clear logic and realizes that the Jedi and Sith feud only creates ruin. He was even apart of the Jedi Sith alliance to take down Valkorian. If more Sith lords were like him perhaps the galaxy might find everlasting peace. That is if the Jedi can get over them selves.