No. I am not a japanophile even though I like some anime and all the progress the japanese made in fields of science and technology particularly cybernetics and electronics of all sorts because I'm very much into that kind of thing.
A katana is just a glorified sword. There's nothing magical about it. The reason the Japanese had to develop such complicated forging methods is because they had no fucking metal in the first place, no, of course, being a hyperbole for "very little". They aren't the only culture to use complicated folding methods for making weaponry. Arabs did it. Russians did it. And so on. It's just that when you have as much metal as most Europe, you don't have to bother. The quality will be about the same, and you wouldn't need overly complicated techniques that take years to learn and perfect for a weapon that's going to be broken and discarded at some point.
So the whole samurai thing in terms of attachment to their often ancestral swords is mainly coming from lack of resources.
Okay, that was a pointless rant. Katana is just a sword. It's illegal, sadly, to own a sword without special permits here in Canada. And even if it was legal, I wouldn't bother. I've done sword classes when I was into Martial arts - it's fun, sure, practical, not very much. Especially not in your average everyday life. A sword is not all that efficient for self-defense when the attacker might have a gun. Sure, there's intimidation, and that's probably of some value, but any weapon will do - and if it doesn't work, you're the one getting shot. Or if you end up killing the guy, you're the one getting hit with manslaughter charge, because there's only this much violence you can exert in self-defense given most laws. Not even in the most stereotypically redneck state in the USA (choose your own, I don't know too many states) it would be okay to shoot to kill someone for simply stepping on your lawn without any permission.
So it's value in sense of self-defense is not all that great. It's a fucking sword, it's hard to use it to non-lethally take down possible aggressors and killing people even in self-defense situations might get you in trouble with the law in some cases. And, again, it won't stop you from being shot.
If I ever got the urge to be a serial killer, a katana would still not be my choice. It's a huge fucking sword. A good weapon is a weapon you can conceal. A knife is concealable. A gun is concealable. A shotgun is concealable. A fucking meter-long sword (yeah, they come in different sizes, but that's a reasonable average) is NOT.
So, it's a definite "NO". I do not appreciate much of traditional Japanese - or any, for that matter, culture, so that part to owning a katana is out of the question. I do not currently practice any martial arts - and if I did, I'd try kickboxing this time. Even if I were to do any weapon martial arts, I would not pick a sword. I'd pick a staff, or those kick-ass sticks. Definitely not nunchucks, I've seen too many people bash their balls with them, and they, in general, are of questionable use aside from impressive showmanship (and bruised balls).
Plus I'm by no means rich and still trying to fund my college education, and a real sword - a katana or not, will cost in the range of a few thousands as a minimum reaching pretty unbelievable prices at the maximum. Professional blacksmiths aren't cheap, and that shitty sword you picked up from some uni arts student taking blacksmithing is by no means of a comparable quality with a professional forged sword.
Neither is that Frostmourne replica on your wall. Sorry.
If you're going to practice swordmanship of any kind, by all means, go for it. It's an expensive hobby, it's fun - I've done only very little weapons stuff when I was doing martial arts, and it's definitely exciting even if you're using sticks and bokkens. And you will be, because nobody's going to let you train with an actual fucking sword as a starter. Even if you do fencing with those light-weight rapiers, or whatever they are, they still wear a crapload of armor and don't use sharpened swords... So, uh, yeah.
It's a cool hobby, but you should consider all the costs - the money, the time, and the realization that practically every fight scene you've ever seen is heavily choreographed and unrealistic performance. Skillful, yes. Resembling reality? No.
Edit: And for sheer killing purposes, as if I were stolen away from home and forced to fight in a thunderdome of some kind, I'd still NOT pick a sword. It takes long to be effective at it. A spear is the best bet, there's a reason why it's been among some of the most used weapons everywhere. Good reach, thrusting attacks which are harder to block then swings, and can be used for more domestic purposes... Such as locating the entrance to the Tomb of Horrors.