Thanks a lot guys, really appreciate it.
I agree to tdol's comments: "I wouldn't go so far as to say it's wrong, but I would never use the plural there."
IMO, grammar should never be regarded as the be all and end all of a language. Sometimes even grammar is not 100% correct when used in a real life situation.
I had an argument with a Chinese English teacher yesterday about this sentence. Now, I am not criticising him in any way, but of course, not having had much experience in English language interaction in China, he was looking at this sentence from a purely grammatical perspective. When I told him that native English speakers would use 'is' and not 'are', he would not accept it. From a grammatical point of view, maybe 'are' is correct. but in general, everyday English, it's not right.
That's my view, anyway