Anyone in kde or kdemod should check out a plasmoid called STDIN
. IMO it's one of the best plasmoids available.
Basically it can display the STDIN, STDOUT, or STDERR of any command. As you can imagine this opens it up to all sorts of options.
For instance if you have acpi, sensors, and laptop mode installed you can monitor temperatures, frequency, battery rates, etc. This is the command I run for the top panel:
sudo hddtemp /dev/sda;sensors|grep temp;cat /proc/cpuinfo|grep MHz;cat /proc/acpi/battery/BAT0/state|grep mW
TBH most (if not all) of the temp data can be found in /proc/acpi, so using cat and grep will yield exactly what you need without extra sensor packages.
Another one I use is to tail -f different logs. It's also useful to have it display:
dmesg |tail -20
different options of netstat are great too.
I just thought that I would share that since I've found this plasmoid so useful.