I don't have a favorite yeast. I brew lots of different styles, from Stouts a to ESBs to IPAs to California Commons. I pick a yeast that will work with the style, and that means I use a lot of different yeasts. I brewed an IPA a few weeks ago and used WLP001, which I have used many times before (mostly for IPAs). I brewed a Brown Ale yesterday with WY1335, which I have never used before.
I guess I won't be able to pick a favorite until I have tried them all!!
--GF