I think it's perfectly OK to mix antiques with modern, as long as there is some style/design to the "modern" piece of it. And an Aeron chair has enough design to it that it could work. Where it doesn't work (IMHO) is with the standard issue cheapo black office chair. Please excuse the horrific condition of my home office, but here is how my office is set up. My desk is a ca. 1920s refectory table, and the chair is an Eames knock-off.

You know, I'm just not feeling the chair you chose. It's a good brand but I'd like to see something more stylish. Here's a list of office chairs at Design Within Reach.

Here is a link that might be useful: DWR's Modern and Contemporary office chairs

I know. The chair is too office like (but super comfy). I already thought about an Eames knock-off :)
What other chairs would work that are also reasonably comfortable?

I don't think it works visually (but I am guessing many here will disagree with me.) I think it only works if your decor is eclectic (and then a mismatch fits in.)

I have an antique-looking office desk and had similar trouble finding comfort and something that matched in style. In my home, a modern looking office chair would have been the only thing that looked modern.

What does the rest of your decor look like?

IMO, this is a case where function trumps form. I cringed slightly on a tag-along to Office Depot with dh when he went shopping for a chair for his office ... especially when I heard big & tall bonded leather. Granted, his desk is not an antique and the room decor is definitely eclectic, but having a comfortable chair is crucial no matter what the style. And I have to admit it's incredibly comfortable. Now I know why he chose it.

I think the chair you are considering is too heavy looking for the table you showed in the photo. Something with a lighter visual weight and smaller scale would look better with the desk, IMO. I got around the issue by finding a humongous desk that was painted white, and stripped it down to the mahongany! underneath.

The desk is about 3'x5' and is currently used as a dining table. The rest of my decor is certainly 'eclectic' or rather more of a mishmash of modern/urban country. I've been looking at pictures and many of the chairs that are paired with antique desks or farmhouse tables look very nice but not very conducive to hour-long working. The other considerationis that the chair needs to be height adjustable because I want to use the desk for my laptop.