Dell XPS8700 from Costco (they sell XPS8900s now). Two actually; my son saved his money and bought one too. I found that I could only save about $100 doing my own build with the same components, and it was worth that to me to have a warranty and place to take it back to in case it broke.
i7-3770; not a 3770K, but this is an appliance, not a gaming rig, so no overclocking needed. 12GB RAM, 250GB SSD main drive, three 1TB secondary drives, one for Windows, one for Linux (Mint 18 Cinnamon under VMware), and one for backups.
Two-port KVM for this and my work computer, since I work from home. ("I got yer open plan RIGHT HERE, pal!")
Watch the prices in your Costco ads, and when the machines go on sale, which they do a few times a year, grab one.