dstat is a versatile replacement for vmstat, iostat, netstat, nfsstat, and ifstat. It includes various counters (in separate plugins) and allows you to select and view all of your system resources instantly; you can, for example, compare disk usage in combination with interrupts from your IDE controller, or compare the network bandwidth numbers directly with the disk throughput (in the same interval).
Raven's System Stats allows users to collect detailed information about an operating system, including kernel architecture, distro, operating system, kernel version, glibc version, name of login shell, number of CPUs, CPU description, hyperthreading support, CPU MHz, CPU cache, bogomips, used and total RAM, used and total swap, filesystem size and type, uptime, unique users logged in, total login shells, currently running processes, total processes since bootup, load average, X resolution, and the number of X servers running.
mpt-status is a query tool for accessing the running configuration and status of LSI SCSI HBAs. It is a heavily modified version of the original mpt-status-1.0 tool written by Matt Braithwaite. It allows you to monitor the health and status of your RAID setup. Currently supported and tested HBAs are the LSI 1030 SCSI RAID storage controller and LSI SAS1064 SCSI RAID storage controller. Since the tool uses the MPI (message passing interface), chances are high that the basic information regarding RAID status will be available for all LSI-based controllers.