I am a big fan of "darker" beers for a winter warmer...meaning Russian Imperial Stout, Barleywine or Old Ale for a base. They are bigger beers (can be 8%) and will do their job on keeping you warm on those cold winter nights...If you really want a 6-8% beer, I would lean toward the Old Ale, as it can be a 6% beer, whereas the RIS and Barleywine typically aren't that "small".
I personally like a more malt-forward beer for this style as well, so it would not be a hop-bomb either.
Also, spices are just an option, as John pointed out...they are not law. If you want to spice it, be subtle and add the spices in a "secondary conditioning" step. Start with small amounts and add to your taste, that way you can have the spices as subtle hints or as forward tastes...all depending on what you want.
Hope this gives you some ideas...