I also realize I meant to write "...non-prescriptivist leanings..." as well. I should really proofread more- especially posting in a grammar forum!

Sorry- the line about the college Chairperson should have read, "...the only person who said it wouldn't matter..."

I don't want to sound proscriptive, but it seems to me that even idioms must have standard forms. My well educated linguist friends often argue with me about that, and tell me that language is an evolving thing, etc. I get that. I hear "a sudden" and "the sudden" with about equal frequency where I live, and so I just tried a little experiment- I called a few friends (fiive in all) who I know to be responsible for interviewing and hiring at their workplaces. I asked a simple question: "When making a tough hiring decision between two candidates, and (other things being equal), a potential employee uses the form "all of the sudden," and another uses the form "all of a sudden." Which would you hire?

Four "business-types" told me they would pick the "all of a sudden" candidate. When I asked why, they answered with varying degrees of articulate ness about it, but one answered very succinctly, " because it means he reads rather than watching TV."

The person who said it would matter was a college English Department chair, and given her non-proscriptivist leanings when it comes to standard forms, that shouldn't surprise me!

I can't speak to the global or national level use of forms of this idiom, but what I CAN say, is that where I live, if you want a job, the firm considered more standard in published works (all of a sudden) is a safer bet- unless you are applying as an English prof, and in that case, you may wind up debating this as PART of the interview.