An internet classic: Jane's Wall Collection Christmas Tree
Rustic and charming: Ingrid's Wood & Wood Stool Tree
A reader solution: Anh & Philip's DIY Christmas Tree Chandelier
A bookshelf tree for those with very sparse bookshelves (not sure that exists!).
Martha & Tom have a fantastic how-to post on their wooden tree DIY.
Another reader project: Michael's Musical Christmas Tree
A Post-it-Notes tree from Living Etc.
How about a projected image like the one at the Danish Embassy?
A printout to use to deck the
halls walls from HP.
A horizontal version that fits on a windowsill from Bo Bedre via Emma's Design Blogg