In this video, David Williamson reviews some of his favorite biotech firms. Many analysts have thrown their weight behind Biogen (BIIB 0.40%) and its new BG12 drug for multiple sclerosis. However, David favors Gilead (GILD 0.46%) over Biogen since Gilead has a larger, more diverse product pipeline. Celgene (CELG) is the No. 1 biotech in David's opinion since it also has blockbuster drugs but a PEG of less than 1.0. Amgen (AMGN -0.10%) is a big company with more products in development than most people realize. Overall, for value and future earnings potential, David likes Celgene the best.