[This is a fast-access FAQ excerpt.]
The Little, Brown Handbook (6th ed., HarperCollins, 1995) says:
"Strictly, such as precedes an example that represents a larger
subject, whereas like indicates that two subjects are comparable.
Steve has recordings of many great saxophonists such as Ben Webster
and Lee Konitz.Steve wants to be a great jazz saxophonist like
Ben Webster and Lee Konitz." Nobody would use "such as" in the
second sentence; the disputed usage is "like" in the first sentence.
Opposing it are: earlier editions of The Little, Brown Handbook
(which did not use the hedge "strictly"); the Random House English
Language Desk Reference (1995); The Globe and Mail Style Book
(Penguin, 1995); Webster's Dictionary & Thesaurus (Shooting Star
Press, 1995); Fine Print: Reflections on the Writing Art by James
Kilpatrick (Andrews and McMeel, 1993); The Wordwatcher's Guide to
Good Writing and Grammar by Morton S. Freeman (Writer's Digest,
1990); Word Perfect: A Dictionary of Current English Usage by
John O. E. Clark (Harrap, 1987); and Keeping Up the Style by
Leslie Sellers (Pitman, 1975).
The OED, first edition, in its entry on "like" (which is in a
section prepared in 1903), said that "in modern use", "like" "often
= 'such as', introducing a particular example of a class respecting
which something is predicated". Merriam-Webster Editorial
Department unearthed the following 19th-century citations for me:
"Good sense, like hers, will always act when really called upon",
Jane Austen, Mansfield Park, 1814; "A straight-forward,
open-hearted man, like Weston, and a rational unaffected woman, like
Miss Taylor, may be safely left to their own concerns", Jane Austen,
Emma, 1816; "[...] to argue that because a well-stocked island,
like Great Britain, has not, as far as is known [...]", Charles
Darwin, Origin of the Species, 1859.
Fowler apparently saw nothing wrong with "like" in this sense:
in the Concise Oxford Dictionary, he gave "resembling, such as"
without a usage label as one its meanings, and gave the example "a
critic like you", which he explained as "of the class that you
exemplify". And he used it himself in the passage quoted under
"'less' vs 'fewer'" above. More commonly, though, he wrote "such
... as" when using examples to define the set ("such bower-birds'
treasures as au pied de la lettre, a` merveille, [...] and
sauter aux yeux"), and "as" or "such as" when the words preceding
the examples sufficed to define the set ("familiar words in -o, as
halo and dado"; "simple narrative poems in short stanzas, such
as Chevy Chase"). This is the same restrictive vs nonrestrictive
mentioned under "'that' vs 'which'": "Ballads, such as Chevy Chase,
can be danced to" would imply that all ballads can be danced to,
whereas "Such ballads as Chevy Chase can be danced to" would not.
"Such ... as" is now confined to formal use, and for informal
restrictive uses where the example is not introduced merely for the
sake of example, but is the actual topic of the sentence, "like" is
now obligatory: "I'm so glad to have a friend like Paul." Guide
to Canadian English Usage by Margery Fee and Janice McAlpine
(Oxford, 1997, ISBN 0-19-540841-1) rightly points out that "such as"
would not be idiomatic here.
Modern American Usage by Wilson Follett (Hill and Wang, 1966)
says: "Such as is close in meaning to like and may often be
interchanged with it. The shade of difference between them is that
such as leads the mind to imagine an indefinite group of objects
[...]. The other comparing word like suggests a closer
resemblance among the things compared [...]. [...P]urists object
to phrases of the type a writer like Shakespeare, a leader like
Lincoln. No writer, say these critics, is like Shakespeare; and
in this they are wrong; writers are alike in many things and the
context usually makes clear what the comparison proposes to our
attention. Such as Shakespeare may sound less impertinent, but
if Shakespeare were totally incomparable such as would be open to
the same objection as like." Bernstein, in Miss Thistlebottom's
Hobgoblins (Farrar, 1971), agrees, calling those who object to
"German composers like Beethoven" "nit-pickers".