Blue-White Anakin or Obi-Wan Saber from Star Wars 77.
I also like Luke’s Green Saber with the Obi-Wan hilt from ROTJ.
In Kotor II i liked Viridian, Silver and Orange colors with a double blade.
If i have to absolutely pick one its Luke’s Return of the Jedi. Which also happens to be the color of Yoda and Qui Gon saber’s coincidentally or Lucas was lazy.