Well, I don't think the AFI poll is really indicative of viewer tastes in the U.S. The problem was that they asked far too many people--and far too many who probably don't know a whole lot about the American cinema--to be a part of the poll. Critics, academics, and other cineastes were, of course, include, but so were Hollywood types and some average Joes (at least when it comes to film knowledge). I assume that the results would have been quite different, and hopefully not quite as embarrassing, had those asked for their opinion been restricted to people in the first group. Quite simply, the problem with the poll was that it was far too democratic. Too many people were asked to place votes concerning the entire history of the American cinema, and I don't doubt that a lot of them think the history of American cinema began with Citizen Kane (or Gone with the Wind). I suppose this has something to do with the widespread American distrust of experts and pointy-headed intellectuals of all sorts. Perhaps that not such a bad thing in some ways, but there's no denying that it can give rise to some serious dumbing-down, as the case of the AFI poll distressingly reveals. What I found most distressing about this poll is that here was a chance to introduce the public to a lot of films (e.g. the entire silent era, Keaton's films, Fuller's films, Welle's films other than Kane, Ray's films other than Rebel, etc.) they'd probably be unlikely to hear about otherwise, and instead it ended up as an extremely boring and conservative list of most of the same old American films that everyone talks about anyway and that can be found at any old local video store.
I can't really fault the votes for not voting for Sunrise, however, as it's nearly impossible to see. I was only able to see it through my university film society, and even then it was in a battered and bruised 16mm print. I think it was once released on video (by Fox, I think, and so probably in a fairly decent print) here in the states, but that's now been out-of-print for years and is nearly impossible to find (and is quite costly when you can find it). I think it's been released here and there by other, small distributors, but those copies, which I assume come from inferior source materials, are almost as hard to find and nearly as expensive when you do find them. This, and the widespread ignorance about foreign films--only about five people showed up to the university film society's screening of Sunrise--makes the failure to include Sunrise rather understandable.
Still, I gather that Sunrise is soon being released on DVD here, and especially when coupled with its ranking in the recent S&S poll, this can only help to get it more exposure here in the U.S. So who knows, maybe it'll show up on the next AFI list. (And I'm sure there will be another one of those in the not-so-distant future, since the first got so much press.)