No I don't want one.
For self-defense it would have about the same effect as a baseball bat. Even with a katana you have to be close enough to hit them, and if you get somebody in the head with a bat they wouldn't be a threat anymore. Hitting them in the arm or the leg would injure them enough for you to incapacitate them. Sure running at someone with a sword would be more than enough to scare them away, but so would running at someone with a bat in most cases. Theres pretty much no practical use for a katana anymore. Especially since, you know, guns came around.
As for decoration yeah it'd be pretty and neat, but it's not my thing. I don't care to be my favorite anime hero much. Not that I have one. It would be interesting as a piece of history, but not much else. There are plenty of things that i'd like to hang on my wall before a katana.