One of the spiffiest little tools I've run across is something called GKrellM. (Pronounced ``Gee'' followed by krellm, like ``bell-m'' in ``antebellum''.) If you've ever seen the science fiction classic Forbiden Planet with Leslie Nielson, Walter Pigeon and Anne Francis, you'll remember Dr. Morbius's secret laboratory, which was left behind by an extinct species called the Krell. Their advanced technology enabled them to alter their physical world by thinking alone (I said this was a great scifi classic!), but it also led to their extinction. Morbius's and the Krell's secret labs had walls full of monitors and displays which helped them measure their mental power, among other things. This desktop utility is named thusly: ``G'' (because it's built with the GTK toolkit) ``Krell'' (because it's really advanced and spiffy looking like the Krell were) and ``M'' (for system monitors). Lots of the screenshots you see at themes.org will display this great looking little system monitor.
GKrellM contains all the basics you need on your system in a handy little toolbar. There're monitors for CPU, Proc file system, Disk(s) and file system usage, disk and file system mount status, disk I/O, and network interfaces. There're also spiffy displays for new mail, system uptime, calander time and date, hostname, memory and swap space usage. There're also handy, customizable buttons you can push that start your upstream PPP connection or fetch your mail, using your desired methods. You can even watch and mount local and remote filesystems. There are also pluggins for XMMS, the X Multimedia System for playing MP3's, and for displaying stats from remote systems you're keeping an eye on, and for some mixer controls.
The main site for GKrellM is http://www.gkrellm.net. Here
you'll find a FAQ and documents for explaining themes and
pluggins and for related information. You'll also find a link to
themes , also known as ``skins''. (See
http://www.muhri.net/gkrellm/.) You can download a tarball of all
themes from
http://www.muhri.net/gkrellm/GKrellMskins-all.tar.gz.
No matter what your desktop looks like, you can find a theme that
suits you. See Muhri's screenshots at
http://www.muhri.net/nav.php3?node=screenshots. Those are
just a few ideas. Image how many variations there must be in all
the themes (currently about 150 themes). There are
modern as well as classic themes. There are artistic as well as
practical themes. There are plain as well as experimental themes.
Geez, there are a lot of themes.
Like most geeks, I'm really a fan of blinky lights and pretty little graphs that describe arcane stuff about my computer. GKrellM is almost even better than piping /var/log/messages to the root window. GKrellM won't replace all your handy command line utilities for really digging into your system, but if there's something it lacks, you can always write a plugin for it (see the plugin programmer's reference at http://newweb.wt.net/~billw/plugins-reference.html). GKrellM will give you a nice overview of what your system is doing at any given time. Then, if you desire more detail after spotting something, you can use commandline utilities to dig into it and research your concern.
There are a host of plugins you can download and compile for GKrellM. Take a look at http://newweb.wt.net/~billw/Plugins.html. There's even a plugin that allows you to control XMMS (www.xmms.org) from GKrellM. I suppose this is handy if you don't like to have XMMS show up on your display all the time. Personally, I think XMMS is awfully cool looking, so I just have it displayed all the time. Since XMMS supports plugins for just about every audio/video codec known to human beings (except Sorenson Mpeg, sob sob), you really have a lot of power from this XMMS plugin for GKrellM.
Other plugins include Gkups (monitors your UPS), GKrellMRadio (controls AM/FM radio cards), GKrellMWeather (shows a brief and current weather report), gkrellmwho (displays who is logged into your machine), Seti@home (a Seti plugin), Mailwatch (monitors several mailboxes, an improvement over the default mail spool monitor), GKrellDnet (monitors current work unit progress of www.distributed.net), GKrellM-Wireless (monitors bandwidth over a wireless PC card), and SNMP (monitors remote systems using the SNMP protocol). See the plugin page mentioned above for more plugins.
If you have multiple hosts on your local network, GKrellM can
help you too. Aside from using the SNMP plugin mentioned above,
you can export GKrellM from the local X display to a remote X
display. Let's say you wanted to export a GKrellM session from
yourbox.yournet.com to otherbox.yournet.com. You simply launch
GKrellM with a function or script on yourbox.yournet.com like
export DISPLAY=otherbox.yournet.com:0.0; gkrellm. This
assumes that you have used xauth or a similar utility to
add permissions for ``yourbox'' to export an X display to
``otherbox''. It also assumes that your network is secure enough
where exporting an X session is not a ``bad idea'' (TM).
I should tell you that at this point GKrellM works just fine on FreeBSD (I have only tried it on FreeBSD). It's in the ports tree, but I wouldn't compile there unless you have space and time for compiling all of the necessary gnome-related sources. If you have GTK development libraries installed, you can simply compile GKrellM in /usr/local/src, which is what I do. I use it all the time on FreeBSD.
There are a couple of articles online about GKrellM you may wish to
check out: http://linux.com/newsitem.phtml?sid=60&aid=8612
and
http://www.linuxcare.com/viewpoints/ap-of-the-wk/04-28-00.epl.
All in all, I think you have to give GKrellM a try. You owe it to yourself. I think the chances are quite high that you will be glad you did.