To go with my new workstation I invested in a Ergotron LX Triple Display Stand (#33-296-195). It seems expensive, but given what you get it really isn't.
I will post some pictures eventually. To get an idea of the size of this thing, watch the YouTube video here, courtesy of motherboards.org.
Obviously it's large, so one significant concern I had was how (or if) it would fit on my desk. Unless you have a deep 'boss' desk, you might be restricted as to the total depth you have available.
As you can see in promo pictures, the stand has a foot, a post, an arm, and a mount that joins the arm to the post. In my case, the size and positioning of the mount was important, because I wanted to put a shelf behind the stand.
A few points that may be helpful on this stand:
The stand will need to be about 9-1/2" away from the front edge of your desk, minimum. Otherwise you won't really have enough space to make a standard keyboard work.
The mount sticks out backwards quite a ways. However, even at the worst case, the arm mount does not extend beyond the rear edge of the foot. In other words, the foot of the stand dictates your overall clearance requirement.
The foot is 15.8" (40.2 cm) deep, front to back.
The arm is 45.25" (115 cm) wide and is on an arc. The arc is 5.5" (14-14.1 cm) deep at the deepest point, measured from the front faces. Do the geometry yourself if you're curious as to the angle.
At the lowest possible adjustment, the arm is positioned about 11" from the floor, measured to the middle of the arm. This will be the lowest center point of your monitor.
At the lowest possible adjustment, the mount sticks backwards between 9-1/2" and 12-1/2" from the floor. In other words, it's 3" tall and centered 11" off of the floor. This is important to know if you intent to position anything else, like a shelf, behind the stand. If your shelf is lower than 9", it will not hit the mount, and you get more depth.
Putting the stand against the back wall, and measuring 7" off of the floor, the maximum depth before you hit the post is about 2". Setting things up so your rear equipment "misses" the mount nets you an additional 2 inches.
I know some of this will be hard to visualize; hopefully the pictures will make it clearer.
I should note that setup for this thing is trivially easy, as it is almost fully assembled. It needs only 4 screws to put it together. The post is the heavy item, with an inner core of extruded box steel that must be extremely strong. This is not a cheap post-and-bolt setup - it looks very high-tech and is very well made.
The spring mechanism has no way of locking it, so you can't pre-position the stand to test fit. You'll need to add monitors, or some other kind of weight, in order to get the stand to position and stay in place. Otherwise the arm will simply fly up to the top position and stay there.
You should also know that although the foot is very strong, the rear part of the foot that extends behind the post is not. It is a separate part that is screwed to the post with two small screws, and is intended only for cable management (according to the manual). If you lean on the spring-loaded arm to force it down, you may lever the post on to the rear guide and damage it (like I did).
Anyway, in my case, I have to cut my rear shelf down from 14-1/2" to 9-1/2", which looks like it will work out OK. I won't really know until I get it all set up.
[Edit]: Pictures available here.