word choice - Which is correct: "__ is different from __" or "__ is different than __"?

As someone who learned English later on in life, I was taught that different from is the correct grammar to use: this is different from that. However, it seems these days everyone uses different than instead. I know it's incorrect usage, but does the language evolve if the majority wins?

Edit: Some commented different than is American English and different from is British English, both are OK. IMO, this isn't like color versus colour, though.

Than is used after a comparative adjective, e.g. taller than, whiter than. The word different isn't a comparative adjective, unless used in more different than. Logically, it makes no sense to say different than.

Answer

You left out the construction that makes the question more interesting: different to.

The quick answer is that "different from" is always correct and acceptable everywhere, but "different than" is common in US usage (as odd as it may seem for two things to be both different than the other), and "different to" is common in UK usage (as odd as it may seem to have both "different from" and "different to" mean the same thing).

Here's the useful alt.usage.english FAQ entry in its entirety:

"Different from" is the construction that no one will object to. "Different
to" is fairly common informally in the
U.K., but rare in the U.S. "Different
than" is sometimes used to avoid the
cumbersome "different from that
which", etc. (e.g., "a very different
Pamela than I used to leave all
company and pleasure for" -- Samuel
Richardson). Some U.S. speakers use

"different than" exclusively. Some
people have insisted on "different
from" on the grounds that "from" is
required after "to differ". But
Fowler points out that there are many
other adjectives that do not conform
to the construction of their parent
verbs (e.g., "accords with", but
"according to"; "derogates from", but
"derogatory to").

The Collins Cobuild Bank of English
shows choice of preposition after
"different" to be distributed as
follows:

                "from"  "to"    "than"
                -----   ----    ------
U.K. writing    87.6    10.8     1.5
U.K. speech     68.8    27.3     3.9

U.S. writing    92.7     0.3     7.0
U.S. speech     69.3     0.6    30.1

So it's safest to avoid both "different to" and "different than", even though they have ≈30% popularity in UK and US speech respectively, and use "different from" exclusively. See also Michael Quinion's World Wide Words where he points out that many good writers have used the much-maligned now-grudgingly-accepted "than".