[QUOTE=Otto]
Fewer.
[/QUOTE]
I’ll repost what I’ve posted before about this silly little old wives’ tale:
You have been taught, through no fault of your own, an appallingly widespread but absolutely incorrect fact about the rules of English. Let me quote Merriam-Webster’s Concise Dictionary of English Usage (link to the relevant portion):
[QUOTE=MWCDEU, bolding mine]
Here is the rule as it is usually encountered: “fewer” refers to number among things that are counted, and “less” refers to quantity or amount among things that are measured. This rule is simple enough and easy enough to follow. It has only one fault – it is not accurate for all usage. If we were to write the rule from the observation of actual usage, it would be the same for “fewer”: “fewer” does refer to number among things that are counted. However, it would be different for “less”: “less” refers to quantity or amount among things that are measured and to number among things that are counted. Our amended rule describes the actual usage of the past thousand years or so.
As far as we have been able to discover, the received rule originated in 1770 as a comment on “less”:
“This Word is most commonly used in speaking of a Number; where I should think ‘Fewer’ would do better. ‘No Fewer than a Hundred’ appears to me not only more elegant than ‘No less than a Hundred’, but strictly proper.” --Baker 1770
Baker’s remarks about fewer express clearly and modestly – “I should think,” “appears to me” – his own taste and preference.
…
The OED shows that “less” has been used of countables since the time of King Alfred the Great – he used it that way in one of his own translations from Latin – more than a thousand years ago (in about 888). So essentially “less” has been used of countables in English for just about as long as there has been a written English language. After about 900 years Robert Baker opined that “fewer” might be more elegant and proper. Almost every usage writer since Baker has followed Baker’s lead, and generations of English teachers have swelled the chorus. The result seems to be a fairly large number of people who now believe “less” used of countables to be wrong, though its standardness is easily demonstrated.
[/QUOTE]
A lot of examples then follow to back up the assertion that “less” used with countables remains, as it always has been, a perfectly standard usage.
So, basically, what we have here is a feature of English that has been thoroughly ordinary for more than a millenium. About two hundred years ago, some guy came along and expressed his own idiosyncratic preferences, but this never really took on with the English speaking public at large, and thus never really became a true rule of English grammar, though it ended up being codified nonetheless in an awful lot of wrongheaded usage guides, the sort which rarely bother to take a glance at reality. (Another choice quote from the excerpt: “This approach is quite common in handbooks and schoolbooks; many pedagogues seem reluctant to share the often complicated facts about English with their students.”)