but if i was to add trim to my living and kitchen-because it is a continuous large room and open (there is no doorway or frame between the two to seperate the room) i would do that trim in the same color/stain. But if I was to do trim in my bedroom and my kitchen-they are seperate entities and treated like such. Unless you have the same decor thruout your whole house, which is highly unlikely so I would stick with the color or stain that matches the decor in that particualr room.
But like the previous person said-if you plan on selling it keep the color uniform thruout and a very basic color...whites/offwhites/stains. Since many people have different furniture and colors, you do not know what the next owner will have. But if you plan on living there forever or a long time then I would go with a basic color that you really like-but do not go with a "fad" color-like a yellow car , becuase if you change your decor the next season then it will not go and you will have to go thru all that work again to repaint/restain to the color of your new decor.
One thing to consider, if you have nice wood trim made of oak, maple or quality pine, best not to paint it, but to stain it instead. Nothing irks me more than looking at a house that had nice hardwood trim and seeing it covered in a coat of paint. On the other hand if it is cheap trim, paint it.