By any other name would smell as sweet;
So Romeo would, were he not Romeo call'd,
Retain that dear perfection which he owes
Without that title."
—Juliet in Shakespeare's Romeo and Juliet (1594)
Researching a possible trek in Nepal this fall, I was reminded that the penultimate point on the planet, rising 8,849 meters or 29,031 feet above sea level, is now known by four different names from four different cultures. (Note: the altitude can vary with the snow depth on the summit ridge.)
The first, and most universal for now, is "Everest." In 1865, it was named, against his wishes, for British mapmaker Sir George Everest (1790-1866), who as Surveyor-General of India directed the Great Trigonometric Survey (GTS) of the Himalayas for the East India Company. The survey took decades, made its officials (including Everest) quite wealthy and measured the altitudes of Everest, K2, Kanchenjunga, and many other monster peaks of the Himalayas.
The Survey was amazingly accurate: Everest was assigned an altitude of 29,002 feet in 1856, only 29 feet lower than the current estimate based on advanced technologies. (The Survey actually determined the altitude of Everest to be an even 29,000 feet, but added 2 feet on the theory that such a round number would look too much like an estimate.)
Major geographic features have often been named after famous westerners, including Alaska's McKinley, the highest summit in North America, named in honor of one of the most contemptible U.S. presidents. This selection was a purely political maneuver by a prominent gold miner who supported McKinley's drive to retain the gold standard in the face of a serious challenge by rival William Jennings Bryan.
Nowadays, most climbers, and many Alaskans, prefer the original Athabaskan name: Denali, or "the great one." It's only a matter of time before Congress approves a bill formally renaming the massive peak, which from base to summit (altitude 6,194 meters or 20,320 feet) qualifies as the world's tallest mountain.
"Everest" seems unassailable for now despite the far more imaginative names given to the peak by the Nepalis and Tibetans, the actual inhabitants of the region whose countries share the summit:
- To Nepalis, Everest is Sagarmatha, which has been gloriously translated as either the "Forehead of the Sky" or (based on the Sanskrit root) the "Churning Stick of the Ocean of Existence." [Chew on that for a while, Sir George.]
- To Tibetans, Everest is Chomolungma, "Goddess of the Wind" (sometimes translated as "Goddess Mother of the World"). 
- Qomolangma, while very similar to the Tibetan name, is the transliteration preferred by the Chinese rulers of Tibet. The Chinese version of the name can be traced back to Chinese imperial surveys of the region beginning in 1717.
The Tibetan Chomolungma is equally entitled to recognition. It has ancient origins and the Tibetan approach is of great importance in the history of Himalayan mountaineering. The first major attempts on the peak were mounted from the north via the Rongbuk glacier and North Ridge. This route frustrated all attempts  until a Chinese expedition reached the summit, without using bottled oxygen, in 1960 — seven years after the first ascent up the somewhat less difficult South Col route from Nepal by Tenzing Norgay, a Sherpa, and Sir Edmund Hillary, a New Zealander.
Meanwhile, the Chinese have been aggressively demanding the formal adoption of Qomolangma since 2002: "Until today the world is still persistently humiliating Mt. Qomolangma with English-language hegemonism." The Chinese position completely overlooks the Nepali claim and insists on the Chinese transliteration for a landform that has a (presumably) much older Tibetan spelling. "Hegemonism," indeed.
The Pacific Northwest is no stranger to these conflicts, as evidenced by the fact that not a single major stratovolcano retains the name it was given by the indigenous people of the region. All these great summits — Rainier, Shasta, Adams, Hood, Baker, St. Helens, Glacier, Jefferson, the Three Sisters, McLoughlin, Lassen — retain the names given them by European explorers and settlers.
While I don't have any particular grudge against John Adams (whose name is shared by seven other mountains in the U.S.), either Klickitat or Pahto seems like a more suitable name for the third highest mountain in the Cascades.
So what'll it be? Everest, Sagarmatha, Chomolungma or Qomolangma?
As often happens, the naming of geographic features has become hopelessly entangled with politics, national pride and the history of imperialism. These delicate questions will have to be resolved at a later date by, ironically enough, legislators and mapmakers like Sir George Everest.
 Trekking in Nepal by Stephen Bezruchka (2000).
 Recent investigations failed to determine whether George Mallory and Andrew Irvine, members of a British expedition in 1924, reached the summit before disappearing. Mallory's body was recovered high on the mountain (at 8,159 meters or 26,768 ft) in 1999.
PHOTO: The "Mountain Formerly Known As Everest?" A view from Kala Pattar showing the summit from the west, the South Col (the high pass on the right horizon), the Khumbu glacier icefall (lower left) and the west flank (right) of Nuptse. [Wikimedia Commons]
AFTERTHOUGHT: Many major peaks retain aboriginal names even in countries that were European colonies. In fairness, I'll list a few: Kilimanjaro (Kenya/Tanzania), Aconcagua (Chile/Argentina), Kanchenjunga (India/Nepal), Popocatapetl (Mexico), Fuji (Japan, never a colony). K2 is in such a remote corner of the Karakoram (thus the "K") Himalaya that it may not have had a local name. Finally, it should be noted that the GTS had a policy — flexible, as it turned out in the case of Sagarmatha — to use local geographic names wherever possible. Most Himalayan place names follow suit, with relatively few exceptions.
Michael Desfeyes, in his interesting compilation on the origin of mountain names, doesn't bother to include "patronymic names like Mt. Hood, McKinley, Everest, etc."
UPDATE (9/5/09): The editors of EverestNews.com, a comprehensive blog about Himalayan mountaineering, have put together a convincing and well-researched theory that George Mallory succeeded in reaching the summit of Mt. Everest in 1924 and died during the descent. Sandy Irvine, his climbing partner, also died during the descent but his body has never been found. According to this hypothesis, Mallory and Irvine agreed to separate so that Mallory could push on to the summit alone. This theory may never be proven (or disproven), but Mallory and Irvine at least came very close to the top of Everest 29 years before the first documented ascent.