Linux only: Conky is a free, open-source system monitor, but pegging it as just a CPU/memory/process watcher is a bit unfair. Conky can keep track of your unread IMAP mail, show what music's playing right now, and pull off more than 250 other data stunts using its built-in variables. It's not a new app—in fact, it's pre-packaged for most Linux distros by now—but we've (surprisingly) never given Conky a featured post before, and it well deserves one. Conky is a free download for Linux systems only; Windows and Mac users can get similar stats with Samurize and GeekTool, respectively. Got a favourite Conky config trick or script to share? Post it in the comments. Screen cap by LH reader Regac.