HP ZR30w 30" monitor.
After selling the iMac and buying Mac Pro I was down one monitor. For a couple weeks I used my old 17" as a second monitor along with a 24" monitor. I knew that was temporary while I decided on my new monitor. I could go for another 24" and have a matched pair, but I wanted more space. I could go 27", and even go with a new iMac that would run as a second computer, but also provide a display for the Mac Pro. However, the more I thought about things, the less I wanted a second desktop computer to maintain and the more I wanted an even bigger display. The problem with the 27" ones are they are a 16:9 ratio and I hated giving up vertical space. The 30" are 16:10, so I keep the ratio of my 24".
In the end I made a good choice, it is the HP ZR30w. It's a pretty stunning monitor. I'm pleased with it. There are likely better monitors from NEC, etc, but this one is 1/2 the price of those ones. It's an anti-glare matte (vs glossy) which was a big factor in my decision. I don't see any bad pixels on it. Pretty amazing considering there's over 4 million of them each consisting of 3 colour elements.
I've set them up with the 24" as a portrait monitor to the left of my primary monitor (30"). It's a pretty nice setup, gives me long pages for web browsing and hugh space for photo work.
Resolutions are 1920x1200 and 2560x1600 respectively. I.e. The 30" is about 80% more pixels over the 24". Interestingly, the pixel size is about the same as my 17" laptop, which is quite a bit more pixels per inch than my 24" monitor. The side effect of this is when moving a window from one screen to another it changes size.
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain