My favorite lightsaber is my own. I made it to reflect the designs of Obi-Wan's TPM/AOTC saber, but with a curved hilt like Count Dooku's saber. It's made out of metal, and other than the parts that were purchassed and then put together, I made it entirely by hand.
As for movie sabers, I have several favorites.
For pure extravegance: Master Windu's electrum plated saber.
For actual use: Count Dooku's curved saber.
For most interesting design: Obi-Wan's TPM/AOTC saber.
For most elegant design: Qui-Gon Jinn's saber