Good question. I haven't a clue. Maybe you can share your opinions on the matter? I don't really wory too much about these types of things.
I use display:none in a comment spam filtering thingy, but that's pretty much it.
I'm just thrilled to death that we're even having this conversation, let alone it being above the fold. The A&U Forum [webmasterworld.com] tends to be a bit quiet, and I think that this is important stuff. From an SEO standpoint, I have it on good authority [webmasterworld.com] that good accessibility==good PR.