You can't go wrong with any Belgian, imo.
Stick with any Flanders style if you like the tart/sours. You can also go Geuze or Lambic for some funky flavors.Mort Subite is a common favorite.
My personal favorite is Leffe Bruin as my daily goto beer.They also make a Christmas and Royal that are very tasty. Grimbergen Bruin also has a tart/vinegar taste that I enjoy. Carolus Classic is one of the most flavorable beers I've had. I use it to make my Flemish stew and it always turns out rich and delicious. If you're following a recipe, skip most of the water/stock and just use the Carolus for all of the liquid. It comes out so rich. Serve over fries.
If you want to go dark/strong, then get St. Bernardus Abt 12 or Westmalle Dubbel. The Abt 12 is the closest you'll get to the best beer in the world, Westvleteren 12. Technically,it's what Westvleteren used to be prior to 1992. St. Bernardus also makes a Christmas Ale that's delicious, but harder to find.
Gordon Christmas Ale is one of my favorites of the season. It tastes like the yummy burnt syrupy edges of pancakes to me. Weird, I know, but that's what I get.
So many choices, so little time. My handle on unTapped is the same as on here. Enjoy!