This is the toughest question for a beer drinker, and one that may change as life goes on, but everybody has a favorite.
I discovered my new favorite recently when I was on a trip to Toronto to visit friends. We ate dinner at the Beer Bistro on King Street in a private room after going to see a hockey game, it was an amazing experience and I got to go through 18 bottles of beer from all over the world that night. If you are ever in Toronto, be sure to stop by the Beer Bistro,
http://www.beerbistro.com/.
Anyway, so, being a guy who was born and raised in Missouri, I have an affection for Boulevard beer. My favorite for regular drinking is without a doubt Boulevard Lemon Wheat. I'm also a big fan of Samuel Adam's Chocolate Stout, but that's another story.
I have found something that has taken the crown from Boulevard in my mind:
Samichlaus Bier from Brauerei Schloss Eggenberg
It's a doppelbock, or double bock, and advertises itself as once being the strongest beer in the world. This stuff is sweet, but with a bit of bitter hops undertone, but oh so sweet. It's like nectar. It is definitely strong though, both in flavor and alcohol content.
Funny thing, one of the friends I met in Toronto is German and told me the name translates to Santa Claus Beer. He said according to the story on the back that the beer was brewed only once a year on December 6th to be drank on Christmas of the next year. My bottle was of 2006 vintage, so was fairly young. According to some reviews online, the flavor gets creamier and sweeter (if that's even possible) as the beer ages. It is brewed at Castle Eggenberg in Austria.
So, post your favorite beer, where you discovered it, and some information about it. I'll make an attempt to acquire and try anything you all suggest with time permitting.