Here's my own prediction about the season finale of Heroes, which will air in about three hours: the visions of the future that we the viewers have seen will not be changed in any substantial way.
In some senses, that's a pretty tame prediction. ("News flash: in fantasy/sci-fi series, characters who think they can see the future, actually can! Wow!") And it's not like there haven't been hints, such as this not-quite-as-straightforward-as-it-sounds statement that I read this morning. (That's a spoiler, by the way, so if you watch the show and don't like spoilers, don't click the link like I was dumb enough to do.) But on the other hand, no one wants the horrific dreams, paintings, and prophesies to be true, and there's been plenty of wiggle room in all of them, so there's reasonable doubt about what will happen.
I think the episode "Five Years Gone" will turn out to be accurate, though, at least through tonight's season finale. A glimpse of a grim and scary America ruled by a psycho, a glimpse which ends abruptly when two nigh-omnipotent people get into a battle that looks likely to take a city if not the world down with them - if the "heroes" have any way to avert that, we haven't seen it yet.
Part of what I find interesting about that future is the timeline. Five years may be just a storyline choice by the writers, of course - the soonest things could plausibly get that dire, long enough for characters to have changed a lot mentally but not much physically, etc. But it happens that 100 episodes is the amount of time generally needed for syndication, and of course is a nice, large, round, impressive, milestone number, which is usually reached during the fifth year of a TV show. So I got to thinking earlier today, what if that's not a coincidence? What if at some point along the line, the writers decided they wanted to show a future through time travel, have it happen, and revisit it after the normal passage of time on some appropriate milestone?
What all that boils down to is, if this TV series has set up a story line that takes five years to tell, if these specific characters will have to work and fight for five years to avert an epic disaster, if a possible, still-unreal future is revisited from the point of view of the people living in it... that would be the most awesome thing I can imagine on television.
This would be more appropriate on one of the many fan sites for the show, and just hours before the show comes out, it matters even less than usual, but it's just something I thought was interesting.