Using a SSD as a system disk makes a huge difference for the overall feel of the PC. Everything is so much quicker (except FPS when gaming). My SSD broke and while waiting for a replacement I restored a backup to an old 7200 rpm disk. My PC was so slow, it felt like a different computer. But since SSD are still expensive, I use a 240GB SSD as a system disk and old mechanical disks for storing files and big programs/games. When Windows bugs you to configure a system image backup, do so. It's really nice to have when your disk breaks!
