In 2011 I moved from having a laptop as my main computer all the time back to having a true desktop computer, and for that I went with a 27" iMac (256GB SSD, 1TB internal drive — pre-Fusion Drive machine that I'm happy to leave this way). To this iMac I added 12GB of RAM and my old (but still quite functional) 23" Cinema Display (yes, the original!). You can see a picture of this setup at my TMO workspaces article, which also details the standing desk I use.