whos been truly immortal? they still all have ended up dieing at one point or another? Just curious guessing you mean how they still keep their conciousness intact or like palps going to clone bodies etc.......I was thinking more of throwing stars around etc...lol...destroying solar systems whatnot.....vader even said the power to destroy a planet is insignificant next to the force...lol....Luke has done some amazing things in EU also....falling from space onto a planets surface without a scratch...
Inmortality means very little to the Jedi, a lot of them can do it. QGJ, Obi, Yoda. They may all be powerful but at least two on that list don't even come close to being the most powerful Jedi ever.
Whats the most impressive thing ever done with the force? Well eating is damn impressive although thats not really something you learn thats just something you can or can not do. IMO throwing stars takes the top, to use the force to manipulate and destroy something that affects an entire system. Now thats power.
i dink yoda or anakin or luke had the strongest with the force becuz it wus said that obi wan wus amazed how strong the force was with anakin and yoda told luke that the force runs strong in ur family and yoda is like 900 years old and have trained jedis for 800 years so i'd say one of those 3 are strongest with the force