btw, the monitor arms in the pic are from Innovative Office Products, model
7000-1000 (there are three sub-models depending on weight range). I found it recommended
in a thread on HardForum (finding decent monitor arms for 30" monitors is not easy, unless you are planning on spending a lot of money!). Best price I found it for was at opentip.com (under $200, though it looks like it is a bit higher now, retail is >$300).
Monitor can also be rotated from landscape to portrait, but there are no "stops", it rotates freely. The extension of 24" is what I liked best, and if you buy it with the Flexmount, you can attach it to pretty much anything. The 20" monitor moves around a lot more easily than the 30", simply because the heavy weight of the 30" makes the movement more difficult. But the arm is really solid even with all that weight.