I'm just using some cinnamon and a titch of clove (bouth ground), mixed into some brown sugar so it doesn't just sit on the top, we're going to be handing it out chilled, mix a spoon of sugar/spice in, head over to the fire and grab an iron...
When I use my slow-cooker to mull cider, I usually chuck in a cinnamon stick, a couple cloves, a handful of allspice berries and maybe some cracked nutmeg or sliced ginger or star anise if I have them...
Mulling tea bags now sounds like a good idea, I would not do spicing right before bottling. You want to give it a couple weeks to get infused, and you don't want the spices in the bottles.
I've had mulled wine before too, and one of the other common spices to add aside from what's already listed is orange peel.