First off, I've always used " as I believed it was the only option. Now I'm working with a C++ guy who uses ' instead. I told him it wouldn't validate, but it does?? (I didn't check his doctype however..)
I did a little investigating at the good 'ol W3C and found although they accept both, ALL W3C examples are shown with ".
In another thread, both Skyzyx and me' insisted that XHTML dictates the use of " for all attributes. Now I'm not doubting either of these guys as I've learnt a fair bit from both, but why???
I'd really like to see some kind of official documentation or just reasoning that I'm not aware of 'cause this one's been floating round in my head for a week or two.