My favorite is Top Chef, but I have recently fallen in love with Master Chef as well. And, although I think the chefs are excessively rude for the ratings, it is a great show.
For a foodie, cooking shows are like porn. So, thank you, Tom Colicchio, Gordon Ramsey, Jaime Oliver and Masaharu Morimoto for baring it all and bringing us the best of what food has to offer.
(Don't worry...the Top Five Best Things About a Restaurant is still coming. Re-freaking-lax.)