You can buy wire trees in various sizes designed for displaying ornaments. Here are some: http://www.ornament-trees.com/

You could also hang pieces of felt on the walls using 3M strips, then stick the ornament hangers through it. Could create a very festive feel. But I'm still hanging onto every bit of autumn here...

I'm in the same boat for the first time this year. I've been considering picking a good spot for some garland to be a focal point and putting some ornaments on the garland.

Al-
my advice is to get some branches (pine or regular tree branches) and place them in a large vase. these make a great base for attaching vintage ornaments without having to get a tree...
good luck.
-casey

Hang them from the curtain rods and chandeliers if you have any. Get some inexpensive egg cups and place one in each for a shelf display. Pick up an inexpensive vine wreath and hook them onto it (I would hang it on a wall, not a door). Wall sconces are also a good place. Hope this helps.

I had this problem. I got a large evergreen wreath and placed some ornaments in that. I've also seen people who place a large piece of lace hanging off the mantle and putting ornaments there (not an option if your cats are as mischevious as mine though...).

My house is craftsman style, with lots of archways and picture rails. I hung garlands in every arch and around the windows and hung my ornaments from them. I also hung the sturdier ones on doorknobs and lesser used cabinets.

I really like jsugarbaker's idea, too, though the cats would destroy it.

you could hang them from the ceiling (in front of windows, in a halo around your dining room chandelier) using monofilament and thumbtacks.

I have a massive window that runs the length of my apartment, so I hang a number of ornaments on suction-cup hooks on the glass. Sometimes, with the cold, a suction cup might come loose and fall, so I don't hang anything fragile this way.

For years we have had little kids that pick ornaments off trees - so we hang ours off the window trellises and they look very pretty with the light shining through them.

I would hang them on a string pulled taut across a room (or along a wall), high enough so they're out of the way. Measure the distance, count the ornaments and figure out the spacing, and tie a series of overhand knots to put the hooks through so the ornaments don't slide around. Once they're hooked through the knots, you can let the string sag, like a garland.

I'd suggest garland or individual ribbons hanging from your curtain rods (I did this when I had little kid visitors and young pets) and some ornaments look great just piled into bowls.

One of the ways I display oversized round ornaments, that are just too big in scale or too heavy for my tree, is to turn them upside down and set them on top of a vase. At Christmas you'll find them throughout my house and at other times of the year those vases hold either fresh flowers or another ball ornament (like an aqua colored world globe or a shell-covered ball).

The living room here at Acorn Cottage is really too small for a tree, but we have an 8 ft wide window, so I ran a long wire across, about 2/3 of the way up. The wire is supported where it crosses the window divisions, and all the ornaments hang from that. The line of ornaments, and the garland of LED lights, look really festive and not fussy

You can see a picture of the decorated window here:
http://www.flickr.com/photos/acorncottage/4072635392/

we have a few that we hang in front of our windows. depending on your window treatment hardware, you may be able to hook some to that!

We have a branch that we spray painted gold and wrapped christmas lights around. Then we hang (and clip on)ornaments. I put picture hanging hardware in it so it hangs off the wall in the kitchen.

@indigoartisanry That window is lovely!!