One vs. two spaces between sentences

Are you a spacist?  Believe it or not, it's a serious question.  Apparently there are two very vehement camps, divided over the issue of whether you should use one or two spaces between sentences.

I have heard before that some people prefer one space, and was even once asked to use one space by a client.  I didn't think much of it, though I did feel rather vindicated not long ago when some style guide or another changed their recommendations to two spaces after sentences.  (I looked it up after the events of the other night, and discovered it was APA style, and they were only talking about rough drafts -- publishing recommendations are still for one space.)

Then the other night a friend posted a very condescending article disparaging double spacing between sentences.  I was amazed at the debate the post kicked off -- and how bitter it got.  Clearly both sides feel completely justified in their choice, but the one-spacists were, on the whole, incredibly venomous about it.

In searching for which style guide it was that changed its mind, I found a much more rational -- and, as it turns out, much better researched -- article defending those who choose two spaces.  Essentially, the Slate author -- and others -- claim that the two-space rule came about because of the shortcomings of typewriters, and since modern technology does not share those shortcomings, two spaces are outdated.  The second article, on the other hand, establishes an astonishingly well-researched paper trail that completely debunks that claim.  Pick up almost any American or British book from the 1700s or 1800s, and you will see long spaces between sentences.  So while it's true that hitting the space bar twice between sentences came about after the typewriter was invented, that's simply because before that, there wasn't a space bar to hit -- once or twice.  The two-space rule was simply established to mimic the precedent that publishers had established over the last couple hundred years.

I think there are very good reasons for a longer space between sentences.  It establishes more white space, and white space -- as we online copywriters know -- generally breaks up text and makes it more accessible for readers.  I also think that like punctuation, a longer space also implies a pause, such as what is found in the natural rhythm of speech: People generally pause between sentences when they speak, and the ones who don't invariably come across as annoying and overwhelming.

I also understand the reasons why a longer space has been eliminated.  The second article points out that the longer space disappeared around the same time as the margins on book pages were shrinking, and other more economic changes were taking place.  It also talks about how modern technology can misread the space, and the people designing the technology had to decide between ignoring extra spaces or letting them mess up the formatting.  (For example, this entire blog post -- like everything else I write -- was written with two spaces after each sentence, but HTML only reads it as one, therefore that is what is displayed on your screen.)

I agree with the author of the second article: Whether you prefer one space or two, that is your prerogative, unless of course you are writing for a client or a publisher that requests it one way or another.  But don't hate on people because they do it differently than you, and don't make up pseudo-historical reasons to justify your preference.

Which side of the debate do you fall on?  Obviously professional writers might have to ignore their preferences sometimes in favor of client or publisher guidelines, but which way do you choose when you have the luxury of that choice?  After my experience with the debate on Facebook, I must ask everyone to please keep the comments civil -- let's keep in mind that statements like "It looks better" are opinions, and everyone is entitled to their own!