Craftdwarfs like to create decorations according to their own likes. I propose that when dwarves are assigned to decorate or engrave a tomb, dining area, throne room, etc. They draw from the likes of the owner of the room, not from their own preferences. In this way, it would be more like a commission, and make more sense then having a dwarf repeatedly engrave pictures of his cat or something unrelated to the interests of their employer.
Another way that room personalization could be improved is if placed items such as chairs and beds were in some way were capable of being replaced according to the whims of their owners. An option would be available when selecting appropriate furniture to 'use any available' instead of +oak chair+. In a public area, dwarves would just grab the nearest applicable piece of furniture, when in a private area, the resident would be able to replace the furniture at will with any other available piece according to his preferences and/or monetary funds (when the economy is back). The dwarf would claim the new item, go to the the spot of the current furniture and deconstruct it. Instead of the icon disappearing, it will revert to the 'under construction' state. the previous object is no longer owned by him, but he is free to put any applicable owned items into use in reconstructing that furniture.
After the object is placed or designated, it can be turned on or off as customizable by a toggle, similar to how fertilizer has a yes/no function. This can be helpful if you don't want your dwarves taking all of your good chairs to decorate their rooms. Along with the deconstruct command and the toggle, a new command 'change materials' would be available allowing the player to change which objects are used in the construction of furniture without removing them entirely and possible having to re-designate. Objects marked as 'use any available' will not be randomly replaced by dwarves if they are in a public area, only private owners may do that.
When the economy returns, dwarves might buy furniture on commission (or have it decorated on commission) to replace their older furniture, which would further increase the personalization of each individual dwarf's home.
I thin this would be a good way to show the individuality of dwarves, as many dwarves (such as those in the military) may never develop craft skills, and will never have their personality really show through with the objects they own or their lodgings, while skilled engravers often get to carve their personality onto every square surface of a fortress (even where it would not be appropriate) What do you think?
Here is an old topic that is somewhat related:
http://www.bay12forums.com/smf/index.php?topic=3281.msg51443#msg51443