Our infrastructure is split up between front end application servers and back end database servers. With the exception of the boxes that serve our images, most of our front end app servers don't really stress IO all that much. The three 12-core virtualized servers at the front end would normally be fine with some hard drives, however we instead decided to go with mainstream SSDs to lower the risk of a random mechanical failure. We didn't need the endurance of an enterprise drive in these machines since they weren't being written to all that frequently, but we needed reliable drives. Although quite old by today's standards, we settled on 160GB Intel X25-M G2s but partitioned the drives down to 120GB in order to ensure they'd have a very long lifespan.