Don't have space inside for a tree? How about a practically-tree-sized wreath on the front door?
This oversized wreath featured in Southern Accents is the only holiday decor visible in the image. Yet it carries the scene, creating a warm welcome when you arrive home and greeting your holiday guests with unmistakable cheer.
This could work on the exterior front door of a single family home or the interior front door of an apartment (provided the hallways aren't too narrow!). What do you think of an oversized, in-your-face wreath as a primary form of holiday decoration?
Image: Southern Accents

Commercial Flour Sa...
Love this!
I can't be the only person who has an irrational fear that someone will steal the wreath off the hook, right?
Oh yeah, that would disappear very quickly in a city. But WOW! it is a beauty.
The dog's face really makes that picture.
Soo pretty!
Very festive! In a similar vein, I took two "half" trees (the kind you would normally place on the wall) and hung them on either side of a French door to make a space saving inside/outside tree.
How fun! I bet it smells great too!
For another fun DIY wreath idea, go to:
http://hautblog.wordpress.com/2010/11/22/make-a-holiday-feather-wreath-with-holly/
I hang my wreath on my security door in Philly. Multiple black plastic zip ties hold it in place and guarantee it won't get stolen. My neighbors use the wreath dangling on a hook technique -- half were stolen in one swoop last year.