Actually, in colloquial speech, it slurs a little to “KILL-uh-MEE-dur”… 
As best as I can phonetically write it out, my pronunciation is:
kih-LAWM-it-er
It’s not quite that cut and dried, but the “lawm” sound definitely gets the emphasis. Oh, born and raised in rural central Mississippi, but I’ve lived around the north eastern U.S. for the last 25 years.
Scotland - (Glasgow)
Kilometre = kilometre
(But you do hear killOMetre too o ften for my liking.
American, born and raised in Arkansas.
We don’t say kilometer down there, there’s no reason to. 
I say kill AH muh ter these days.
United States, Central and southern Florida, also central Kansas, North Carolina, Oklahoma, way to far northern NY along the DMZ in ROK, Turkey and currently in Saudi Arabia :
Ki-LAH-mih-ter though I also use Cliks and Kays. I picked that up from the Army.
ohio, usa.
kill-AH-muh-ter.
USA. Los Angeles, California.
KILL-oh-meter.
Well, this is fascinating.
My impression, from small samples, was that KILometer was a Canadianism, while the U.S. and the U.K. shared the kiLOMeter usage (and I had no clue what Oz and Ennzedd did).
The truth seems to be somewhat different: Much of Ontario and Michigan, and significant parts of the U.K., kill their meters (I form no hypothesis about California until I have more data points). Much of the remainder of all three nations use the -LOM- sound. (Jonathan Chance is, as always, a rule unto himself. ;))
Since proper Canadian English seems to be an admixture of British and of (U.S.) American pronunciations where the two differ, I thought I might have hit on a unique Canadianism. This was not the case; it’s a regional dialect situation.
Just for the record, my own data point: born and raised in upstate New York, 30 miles from Canada, five years in North Carolina, and I use and have heard k’LOM-uh-t’r, where the apostrophes represent quickly slurred schwas – except that Canadian TV and Canadian motorists passing through my home town, and people when I visited Kingston, used the KILL-oh-mee-tuhr rendering.
While we’re at it, Jonathan and anybody else willing to admit to hearing or using the “klick” usage (which I’ve only seen in SF otherwise): Do you more often hear “klick” as a measure of distance or as a measure of speed, equivalent to KPH? My reading indicates a mixture of both but with the more common tendency to use it as shorthand for speed.
I say klicks sometimes but only in reference to distance, never speed. For example: It’s 300 klicks to the city. For speed I always say kilometres per hour. I also pronounce it ki-LO-metres and I’m from BC, Canada.
I first learned how to pronounce things in Iowa where I learned to say KIL-oh-meeter. I attended the State University of Iowa where I learned to say kil-AH-mutter which is my current pronunciation (in California since 1950).
Except when I now and then revert.
Icelandic born and raised.
The usual pronounciation is KEYlow-meh-ter, the northern Icelandic prnounciation is pretty much the same except you spit when you say the T.
…you should hear us pronounce “vaðlaheiðarvegavinnuverkfærageymsluskúraútidyralyklakippuhringur”
Born and bred US Midwesterner/Great Plainer (Missouri born and raised, Kansas for college). Kansas City Metro area my entire life, though my parents are from St Louis, so I say Soda (not Pop), and I grew up saying “warsh” (though I broke myself of that habit in elementary school.
Kill-ahm-eter. Kill-oh-gram. Kee-low for short.
KLAHM schwa der.
Julie
American, more specifically Kansas. I say kuh-LOM-uh-ter
New Zealander, from Auckland, Auckland Province.
Kuh-LOM-met-uh.
Born and raised in rural Wisconsin, outside of Livingston to be exact. I’ll admit that I have a sort of “country ‘n’ western” twang when I get upset, but I have no idea what bearing that has on my pronunciation of kilometer.
kil-AHM-etter, where AHM is a mix between OHM and AHM, but closer to AHM
Sydney, New South Wales, Australia.
KIL - uh - MEAT - uh, with ‘uh’ being my dodgy depiction of a schwa sound, and with the primary stress being on the first syllable, and the secondary on the third.
K’ - LOM - uh -tuh, (stress 2,1,3,4) similar to the New Zealand usage Ice Wolf described, is also used here. I think the two pronounciations would be neck and neck here amongst the Sydney population. Those who choose this second pronounciation reserve it exclusively for “kilometre”: kilolitre, kilogram, kilowatt etc invariably use the first. I’ve yet to hear a person say “k- 'LOG-rum”. I did once have a teacher who said “KYE - lo - gram”, but she was quite possibly mad.
The American military “clicks” is sometimes used, and is universally understood here. The Australian (I think) “kays” is quite common, particularly amongst older people. Anybody over about 50 in Australia is more comfortable with miles than kilometres, and it is these folk who tend to use “kays” when forced to be metric. Talking amongst themselves, however, it’s still miles.
Born and raised in Iowa… Kuh-LAW-muh-ter now… most likely kila-mee-ter in Jr. High when learning metric. But I used to “warsh” my clothes too :0)
in dutch: KI-lo-me-ter.
in english: ki-LO-me-ter.
I believe that, grammatically, the correct pronounciation is:
KI-lo-me-ter.
after all, we have:
MIL-limeter (a thousandth)
CEN-timeter (a hundredth)
DEC-imeter (a tenth)
meter (the unit)
DE-cameter (from the greek deca or ten)
HEC-tometer (a hundred)
KI-lometer (a thousand).
If you look at it from a mathematical point of view, those would be the correct pronounciations.
I think.
Flemish, living in Ireland.