I was in the exact situation as yourself.
I own my own business and own quite a few macs, imacs, mac pro's, even a few mini's.
But for at home My current setup is a Apple Cinema Display 27 with a imac 3.2 21.5. It went through quite a few alterations before I settled on this setup. The imac 27 Cinema display has a better overall temperature profile than the 27 inch imac.
They each have the same display but the 27 imac is alot warmer than the 27 Cinema display, the whites on the imac are not really all "white'. It is hard to tell unless you have them next to each other.
Having a 21.5 imac I have two glossy display IPS panel's in dual screen mode, and have the 27 Cinema display set to 1080P, same resolution as the 21.5.
I have on order a 21.5 quad i7 2.8 with SSD.
If you are using a 27 imac with another display, you're going to have to go glossy. A matte with a high gloss display such as a imac does not work, trust me I did it. Many times.
A high end TN panel will serve your purposes well. I used many monitors such as the Dell 23 ultrasharp, Which is a 'e-IPS panel. Not much better than a high end TN if at all.
This is a good IPS panel as is the Dell. But both Matte. Will not work.
http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/382087-382087-64283-72270-3884471-4101131.html
I have tried a HP TN such as this. I got this idea off of a reviewer off of Amazon.
http://www.shopping.hp.com/product/display/display/1/storefronts/XP599AA%23ABA
I used this monitor in a dual mode setup with a 27 imac. Let me tell you this monitor is fantastic. It is 8 bit TN panel with true 16.7 million colors, glass screen with a 'bright view' treatment. Brightview absorbs the light so you get all the benefits of a Matte with the clarity of a gloss. Best of both worlds.
http://www.tftcentral.co.uk/articles/6bit_8bit.htm
I did not believe it until I saw in best buy the imac side by side with the 25.5 inch HP. I set the imac 27 to 1080P and steped back a few feet. Head on the HP actually looked on par with the imac. It is the best TN on the market right now. As good as it gets for a TN.
It was so good in fact that I got sick of the yellowing issue on my 27 imac and went with the HP 25 inch panel as my main display for a short time and bought a 21.5 to go along with it. The HP as good as the 21.5 after I calibrated the HP monitor. Set the brightness down to 70 and basically matched the imac's color profile.
The drawbacks of a TN panel are apparent when viewed from the side, but this TN panel also has decent viewing angles. I did numerous tests, and it did not do too bad. I eventually went with a 27 cinema display and sent the HP to the office to use with the Mac Pro there. I eventually needed the viewing angles and the HP was not up to par for viewing angles, but if viewing angles are not important the HP is a good choice.
My marketing director still doesn't know it's a TN panel, he thinks its a PVA panel or a MVA panel. He is happy and I am not going to tell him. The panel looks that good.
Check one out before you buy anything, you will have to get a imac stand since the HP is much shorter than the 27 imac though.
