In my humble opinion, Master Roshi was probably the most influential to Goku throughout the saga (kamehaha wave, flying nimbus, training, tournaments, etc). Admittedly, I only made it to the very begining of the Buu series where the show by that time was dealing with some character bloat issues, and my memory is hazy at best. Still, I know nothing of his fate, or if there was one at all. Yes, spoilers are ok if any apply. I would just like to know what happen to one of Goku's greatest teachers.
Old Master Roshi is not changed much, still a little bit of a skirt-chaser and now old as dust, but he is otherwise still the same character as he was when the Dragonball series starts.
Master Roshi's influence on Goku is profound and lasting. It is evident in Goku's behavior through the entire series. Master Roshi survives (as well as any one can be said to survive when wishing is possible) to the end of the Dragonball Saga and is the last person to see Goku before he leaves Earth in Dragonball GT episode 64. (Thank you, Gorchestopher H.)