The Blade of Woe from the end of the Dark Brotherhood questline is another one of those items that just won't stay put. You can put it in a dagger rack if you have Hjerim ( I dunno about the other houses, but this one has 4 ) but as for trying to place it on a surface, forget about it. Always ends up on the floor.
Let me know if you have any cool ideas for decorating as well. I actually came up with a pretty sweet idea and instead of just putting a weapon in one of the display cases in the armory, I just completely filled it and the whole area around it with soul gems. it looks pretty rad.
Oh, and also... if the silvery goblets and stuff in dragonsreach don't do it for you, get the Dawnguard DLC and go into the vampire castle. It has all the goblets, plates, cups, etc etc but they're all spattered with blood. They look pretty sick.
I don't think the blood effect remains on the item after you take it - I think it's a texture specific to the cell, or something. Could be wrong, though.
On a similar note, if I hadn't been in such a hurry to post this guide, I might have also listed where you can find Objects of Unusual Size, and how to use them. The Bard's College is a good place to start - just about every generic item in there is a larger or smaller version of its original self. The Shatter-Shield house in Windhelm has an array of giant and tiny wine bottles, you can find giant kettles in the first area of Ilinalta's Deep, and so on.
Unfortunately (and surprise surprise) patch 1.6 or so kinda mutated the concept of OoUS - when you initially drop them from your inventory, they won't look any different, but after you exit and reenter the cell they should return to their altered size. Another post-patch problem is that you can't have multiple OoUS's of the same item type in your inventory at once without some of them losing their altered status permanently. Still, the patch didn't destroy the concept, it just made it more inconvenient.
And like in all past games, most of the time the OoUS will lose its size if you pick it up a second time and re-drop it - so once you drop it from your inventory the first time, try to avoid picking it up again.
Beauty part is that, given the game's awesome respawn feature, you can get limitless copies of most OoUS's you find. --- Simple questions deserve long-winded answers that no one will bother to read.