I am excited! Though I love my current Mac, and it will have a place in the office behind me, streaming my favorite classical station (WETA.org) and doing some other tasks. The new machine also has a large SSD, which I understand is like flash memory, faster than a HD but retains info like a USB thumb drive.
Of course I had to buy a new printer, and a thunderbolt-firewire adapter... ugh. But also a bigger 27" screen will be nice. My current 21" screen was barely enough to handle a page spread and all the Adobe InDesign menus I needed to have open.