As others have said, I believe the reactions on the monitors are meant to represent the Architect's predictions about Neo's response (or the predictions of some algorithm designed by the Architect, if there's a difference), not the "Ones" from previous cycles. This would fit with the Architect's habit of trying to anticipate what Neo will do next (lines like 'while your first question may be the most pertinent, you may or may not realize it is also the most irrelevant' and 'But we already know what you're going to do, don't we? Already I can see the chain reaction, the chemical precursors that signal the onset of emotion, designed specifically to overwhelm logic, and reason'). It would also fit with the scene where Neo yells "bullshit!" and all the images on the screen do too, and the Architect comments "Denial is the most predictable of all human responses." Finally, it would fit with the scene towards the beginning of their meeting where the Architect was talking about the systemic "anomaly", and all the images on the screen give angry rebellious responses like "You can't control me!" and "You can't make me do anything!", and after observing these images the real Neo comments "Choice. The problem is choice."
I think the aspect that often misleads people is that after the Architect says "I prefer counting from the emergence of one integral anomaly to the emergence of the next, in which case this is the sixth version", we hear various Neos on the screen say lower numbers, which makes people conclude that these are old recordings of other Ones reacting to the Architect saying "this is the __ version" where __ was some lower number. But I think what's actually happening here is that one possible reaction Neo might make would be to mockingly count up from one to five. Go to just after 2:10 in the youtube video of the scene below, or 1:51:50 on the US blu ray, and listen carefully to the numbers being spoken:
For one thing, they are in order, and in spoken in the same flat rhythmic way, like someone counting aloud: "one, two, three, four, five" (there may be a 'six' after that, it's hard to tell). Also, although there is a cut as you hear "one", for the numbers two through five you can see that at the moment it's spoken, one of the Neos on the screens is holding up the same number of fingers, and then the image on the screen where he was holding up those fingers resets, so that would fit with the idea that it's just a single scenario of Neo counting up, but chopped up and displayed on different screens.
There's also the fact that in some shots of the screens, there seem to be more than six different reactions shown--for example, try pausing at 2:36 in the youtube video, or 1:52:14 on the blu ray, showing Neo in a bunch of distinct aggressive poses. I suppose you could imagine that some of these are just chopped-up versions of a series of aggressive gestures by a single previous One, but if you accept that a single reaction can be chopped up and displayed on different monitors, then the fact that he previously spoke different numbers could just be a single counting sequence as I suggested above.
As a final bit of evidence, there is the scene where the Architect offers Neo a choice between two doors, with the door on Neo's right (the viewer's left) allowing him to return to the "source" and reboot the Matrix as previous Ones had done, and the door on Neo's left (the viewer's right) allowing him to enter the Matrix to save Trinity, which the Architect had said would "result in a cataclysmic system crash killing everyone connected to the matrix, which coupled with the extermination of Zion will ultimately result in the extinction of the entire human race." Neo, of course, chooses the door on his left, so the viewer sees him turning to the right...and all the images on the screen turn the same way! What's more, if you watch carefully from about 1:57:18-1:57:19 on the blu ray, they lift their head to begin turning slightly before the real Neo does, but then they begin turning their head to the left (the viewer's right) slightly after the real Neo does, so it can't just be that the Architect has altered the function of the screens to show a live playback of what the real Neo is doing. The fact that they all turn in the same direction as the real Neo isn't consistent with them being previous Ones, but it is consistent with them being predictions about his behavior, since the Architect already seemed to have been resigned to the fact that he was going to make this choice with the comment "Already I can see the chain reaction, the chemical precursors that signal the onset of emotion, designed specifically to overwhelm logic, and reason."
Update: I picked up a set of the official Matrix movie screenplays for help with Matrix-related questions, and I think the Reloaded script makes it pretty clear that the images on the screen were not intended to be "Ones" from previous cycles. For one thing, the non-dialogue, scene-setting parts of the script refer to the images on the screen as "Neos", and their lines are always headed "NEO". But more definitively, after the Architect's line that "this is the sixth version", the script reads:
The Neos respond in a barrage.
There were five Ones before me! That's impossible. It doesn't make sense.
You're lying. This is bullshit. I'm afraid.
If that's true... How could that be?
There are only two possible explanations...
We move towards a specific Neo, centered among the others, closing on
a single line of thought.
...either no one told me, or no one knows.
I've tried to reproduce the script's formatting above--all the "Neo" lines except the "There are only two possible explanations..." and "...either no one told me, or no one knows" are printed off-center in the screeplay, as are all other examples of lines from Neos on the screens that are different from the lines of the real Neo (whereas the lines of the real Neo are centered on the page, along with those of other characters like the Architect). So this makes it clear that "There were five Ones before me!" was one of the lines scripted for a screen-image-Neo (and the counting of other numbers was apparently unscripted), which fits with the idea that the images on the screen were meant to be predictions about Neo's reactions to the Architect's lines, but it doesn't fit with the theory that they were meant to be Ones from previous cycles, since for the previous Ones there would have been less than five before them.