Different countries have different traditions of what they put in their mulled wine. Most use some varietal of red wine, and the key spices usually include cinnamon, cloves and something citrus. After that, additional spice variations range from ginger and peppercorns to honey and cardamom.
The Swedish have their Glogg, which mixes a fruity red wine with port and then adds some of the hard stuff, like brandy or rum. They add cardamom, cinnamon, cloves and ginger to spice it up and then top it off with some raisins and slivered almonds. For a nonalcoholic Glogg, you can substitute orange juice and grape juice for the alcohol.
Germany's Gluhwein (pronounced Glooh-vine) traditionally calls for a dry red wine, some sugar and lemon, and then cloves, vanilla pods and cinnamon sticks for the spice.
Russia's Glintwein is pretty much the same as the German recipe. Bulgaria's Greyano Vino recipe is red wine heated with honey and peppercorns, for a bit of the sweet and spicy. And Italy's vin brule calls for red wine with honey, oranges, cinnamon, nutmeg clove and juniper berries.
As you can see, the variations are vast but the result is the same. A warming drink for wintertime, best sipped in front of a roaring fire.