Want My House to Have the "Holiday Smell"

Janey has the right idea. I have a small crock pot that's for potpourri - I just put in water and add cinnamon sticks and whole cloves, but a pot on the stove works just as well. You can also make hot cider by adding the cinnamon stick and cloves and simmering in a crock pot all day. These ideas also work well in adding a bit of humidity to the air during this dry weather.

Please don't use the plug-ins - those spew toxins.

I'm a big fan of simmering some potpourri on the stove while I'm at home. Or burning different scented candles at the same time (IE: Cinnamon-scented, Pine-scented, pumpkin pie-scented all at the same time).

My mom use to simmer cloves, cinnamon sticks, and I think vanilla in a pot on the stove. She would put water with it and it filled the air.

Not something you can do "all the time" but for a party or special occassion, nothing smells my house up better than heating up some spiced apple cider punch, or mom's holiday punch in the crockpot.
I also like those pinecones: I put them in a pretty basket with a nice bow on it, and put it up on the mantle.

One year I bought cinnamon scented pine cones. The scent was pretty strong at first, but it lasted the whole season. I think I saw some at Albertsons or some other grocery store lately.

I actually just bought one of the Fabreeze holiday plug in smells. I like that brand because it's two different smells that alternate throughout the day, so you don't get used to it and can continue to smell it. The one I got is so good. It just makes me think of Christmas when I walk in.

Yankee Candle has a Mistletoe candle right now and it smells just like a Christmas tree. Also, something else that I do is boil cinnamon sticks with a few cloves and sometimes some orange slices as well-it smells really nice but you should use a pot you don't care too much about. HTH