Oh Oh! This is BY FAR my favorite era other than mondern art. Sorry I know mostly about painting, so I'll go with that.
For my three, I choose one from Northern Europe, one from Italy and them my favorite from this time period.
Northern European renaissance is well known for their use of oil painting which dries much slower than acrylic paint, thus leading to an era of unbelievable realism and symolism. And the winner for most important artist in the Northern European renaissance is: Jan Van Eyck!
http://en.wikipedia.org/wiki/Image:Jan_van_Eyck_001.jpg
The Italian renaissance is known more for their techniques and advancements in depth perception and large scale frescos. So the artist I believe was most influential in this aspect is: Fra Angelico
http://en.wikipedia.org/wiki/Image:Fra_Angelico_043.jpg (Some of the first painted arches)
Then the artist who is one of my favorites, someone who embodied the technologies and techniques of the time, but also did created visions that people would not appriciate until the days of Salvidor Dali - many centuries later. None other than: Hieronymus Bosh
http://en.wikipedia.org/wiki/Image:Hieronymus_Bosch_-_The_Garden_of_Ea rthly_Delights_-_Hell.jpg



