For hardware I'm a big fan of RAID 10 with 4 to 6 drives, and always a hardware RAID controller. Never software RAID. Dell makes a H710-P raid controller that can't be beat. For drives I prefer to keep SQL data on 300gb enterprise raid 10 array and documents and seldom accessed data (like reports, backups, etc) on a separate array of 1-2 Tb. For most office stuff a RAID 10 is going to be far more reliable than a consumer SSD, and far more economical than enterprise SSD which will cost more than taking your entire staff on vacation to the Bahamas.
