I replaced my 2007 MacPro 8-core with 32GB ram with a Eizo 24" ColorEdge display with a 27" iMac i7 with 32GB ram and internal 3tb fusion drive. I ditched my two eSata Sandigital towers for a single Drobo 5D which connects to my iMac via Thunderbolt.
I calibrated my iMac display with ColorMunki. I'm very happy with the results. The Geek Bench score suggests that the iMac is about 40% faster in all of the performance tests than my aged MacPro. The Drobo is loaded with a mix of Hitachi 3TB and 4TB drives. It all works great and is very fast. I love the larger display and the images in Lightroom, Photoshop, Aperture (my iPhoto for family stuff) and Final Cut Pro X all look great and the software performs great too.
I have had my new set up for about 6 weeks now. I'm very happy and have reclaimed a lot of desktop space as compared to my old set up.