Adam Liptak, "Verizon Reverses Itself on Abortion Messages", 9/28/2007, quotes one of the people who didn't like Verizon's (later reversed) decision to bar NARAL from sending text messages to its activists:
“I’m a supporter of abortion rights, but I could be a Christian-right person and still be in favor of free speech,” Mr. Hoag said. “If they think they can censor what’s on my phone, they’ve got another thing coming.”
Google has 146,000 hits for "another thing coming", most of which are not the Judas Priest song, vs. 49,300 for "another think coming", which I'm pretty sure is the original expression. (Arnold Zwicky observed thing's internet victory back in June of 2004 -- though the totals were much smaller then, 21,400 to 5,830.)
Although the OED explicitly agrees about the direction of development
to have another thing coming [arising from misapprehension of to have another think coming ...]
the earliest citation for the "misapprehension" is in 1919:
1919 Syracuse (N.Y.) Herald 12 Aug. 8/3 If you think the life of a movie star is all sunshine and flowers you've got another thing coming.
which is 18 years earlier than the earliest citation given for the "correct" form:
1937 Amer. Speech XII. 317/1 Several different statements used for the same idea -- that of some one's making a mistake...[e.g.] you have another think coming.
The fact that Adam Liptak (and his copy editor) rendered Mr. Hoag's quotation with "thing" means (I guess) that they must think that the "misapprehension" is correct. I'd say that they've got another think coming, except that there's some evidence of internal NYT copy-desk dissension (or perhaps lack of interest) on this point. The NYT archive shows 15 instances of "another thing coming" since 1987, compared to 31 of "another think coming".
Not all of these (on either side of the think/thing divide) are in quotations. Thus Ira Berkow wrote ("Liberty Subdues Jitters, and Nearly Comets", 8/27/2000),
But such desperate talk may well have accorded insight into the hearts and minds of the Liberty players. It seemed they were digging themselves a mental hole, but no one could contest that they had a reason.
For the amateur psychologists, however, they'd have another think coming.
And Christopher Bray's book review "Escape From Ischiano Scalo", 9/10/2006:
Sufficient to say that the novel builds, with heartbreaking clarity, to one character’s utterly unpredictable demise. Anyone who thought “The Bicycle Thief” had told them all they needed to know about injustice has another think coming.
On the other hand, Kirk Johnson "Voters, Their Minds Made Up, Say Bin Laden Changes Nothing", 10/31/2004, has the lead sentence:
If Osama bin Laden imagined, in releasing a threatening new videotape days before the presidential election, that he could sway the votes of Kerry supporters like David and Jan Hill and Bush supporters like Paul Christene, he has another thing coming.
And Judy Battista wrote on 3/6/1999 in "St. John's Gets Revenge, and a Shot at UConn":
The payoff finally came last night when, in the waning seconds of a game full of brutal defense and extraordinary intensity, point guard Erick Barkley, who had promised that Miami had another thing coming if it thought this third game would be a cakewalk, stripped Johnny Hemsley of the ball as the clock wound down to single digits, securing a 62-59 victory over the ninth-ranked Hurricanes and St. John's first trip to the Big East final since 1986.
This one doesn't seem to be in the eggcorn database yet.
[Update -- if you're worried about the time sequence of the OED's citations, here's something to set your mind at ease. Or maybe not.
"What was Due the Professor", New York Times, June 9, 1901 (reproduced in full):
She was a Normal School girl and had taken the Regents' examination in Latin. Comely, well-dressed, alert, and rather "proper" in her mannerisms, she would no doubt take great offense if told that she was so addicted to slang that she dropped into it without having any more than a subconscious knowledge of the fact. And yet this is what happened. The examination was over and the papers were being collected.
"Miss ___," said the chief examiner to the young woman, "did you not look on Miss ___'s paper for answers to these questions?"
"No, Sir," snapped the girl, with eyes ablaze.
"Well, Professor ___ thought he saw you do so."
"Well, Professor ___ has another think coming, " retorted the candidate, who expects some day to have in her care a part of the growing population of New York City.
So it seems that as with "home/hone in on", the two versions of this expression have been more or less in sociological equilibrium since the beginning.]
[Update 9/30/2007 -- Today, a Metafilter post on why 0.999... is equal to 1.0 was hijacked by a debate on "have another think/thing coming". Feelings among the Mefians run suprisingly high on this question. There were 211 comments at last count, more than twice the number of the next most active post for the day. ]Posted by Mark Liberman at September 28, 2007 06:27 AM