Something with some oomph to it, flavor-wise, keeping in mind that the spices will overwhelm any subtlety to the wine's flavor. A decent (if inexpensive) zinfandel or pinot noir should be fine. You're in Italy, yes? Chianti should be fine.
right now I'm eyeballing a bottle of Gnarly Head old vine zinfandel
if you haven't had it, go to walmart and get a $6 bottle. one of my favorite California red wines. think I might use this. wont happen til the weekend though so I'm still open to sugetsions
Gnarly Head Old Vine Zin is great, and good for mulling. Just don't let it boil; add the spices and bring up to serving temperature. Taste as you go, to make sure the spices are right.
I usually go for something in the $10 range. Preferably a higher ABV than lower to really "warm" you up. I also prefer whole spices. Put them in a tea ball or muslin bag. Heat the wine, but don't boil it. I also find that depending on your taste, you need to add a little sugar or honey. When you heat the wine, it can get pretty bitter.