It's been almost three years since I tested my first solid-state drive and that first impression has lasted to this day. Anyone that has used an SSD in their computer will tell you that it completely transforms performance. By removing the 6ms+ delay associated with hard drives, almost everything loads snappier -- often instantaneously.For that reason, we have maintained for years that the single most important upgrade you can make to an enthusiast-grade machine is adding an SSD for your operating system and applications. The key downside to SSD technology is its cost per gigabyte, which is significantly higher than traditional mechanical hard drives. When we published our first SSD roundup in 2009, Intel's X25-M 80GB was the best option available and cost a crazy $4.87/GB. Alternatively, the OCZ Vertex 120GB was available for $340 at $2.83/GB. Although the Vertex was more cost effective, around the same time 1TB hard drives were fetching less than $0.15/GB.