Is it 'OK' for a Christian to have a haunted doll?

I suspect you’re asking the wrong group of people.
There’s nothing wrong with it, because it is meaningless. It isn’t real. If you enjoy your interest in the paranormal, there is no reason that you shouldn’t entertain that, if only just for fun.

Much needed side note: Voodoo and Wicca are religions, followed by plenty of people with good intentions. They’re not “bad stuff” in themselves. At least not more so than religion in general. Oh snap.

As for your question: Sure it’s okay, if you really want to. The fact that you’re a Christian shouldn’t be all that important here. You have to make your own decisions anyway.
But if you’re really hoping someone will talk you out of it, doesn’t that tell you your better judgement says it’s a bad idea?
If this indecision is a tug of war between your better judgement and your morbid curiosity, then don’t do it.

Christianity is about the spirit realms too…....

but haunted dolls sounds icky to me.

Deuteronomy 18:10 There shall not be found among you any one that maketh his son or his daughter to pass through the fire, or that useth divination, or an observer of times, or an enchanter, or a witch.

2 Chronicles 33:6 And he caused his children to pass through the fire in the valley of the son of Hinnom: also he observed times, and used enchantments, and used witchcraft, and dealt with a familiar spirit, and with wizards: he wrought much evil in the sight of the LORD, to provoke him to anger.

Galatians 5:18:24 But if ye be led of the Spirit, ye are not under the law. 19Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,
20Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies,
21Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
22But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith,
23Meekness, temperance: against such there is no law.
24And they that are Christ’s have crucified the flesh with the affections and lusts.

Sinner…

403. FOLLOWING THE DESIRES OF THE MIND Eph 2:3
418. STUDYING THE OCCULT Deut 18:9–14; Lev 20:6; Isa 8:19, Isa 47:13,14 ?
430. NOT BEING PERFECT Mt 5:48; Gen 17:1; 1 Ki 8:61; 2 Cor 13:11
538. SIN, YET NOT KNOW IT, STILL SIN Lev 4:13,14,23
572. THINKING HOW TO FULFILL THE DESIRES OF THE MIND, AND OF THE SINFUL NATURE Ro 13:13,14
655. LIVING FOR YOURSELF 2 Cor 5:15; Lk 9:23
656. LOVING THIS WORLD 1 Jn 2:15–17; Ja 1:27; 4:4
657. LOVING YOUR LIFE Jn 12:25
658. MIND OR THOUGHTS ON THIS WORLD Phili 3:18,19
659. SERVING EARTHLY THINGS Ro 1:25
660. SPEAKING OF THE WORLD Jn 3:31; 1 Jn 4:5,6

lol…Seriously though… Go for it…It’s a doll most likely not haunted

If you like the doll buy it. It’s not haunted, though.
If you believe in Ouiji boards, I suggest you look up the idiomotor effect
http://en.wikipedia.org/wiki/Ideomotor_effect

I don’t think there are haunted anythings, but if there were, nobody should have them.

Christians already believe in resurrection and life after death. If that is not paranormal, what is?