As a dictionary / thesaurus, I use WordNet (type wn in text terminal).  It did not come on my Linux installation CDs, so I had to download it (10 MB) and install. Really worth it. Try: http://www.cogsci.princeton.edu/~wn/

Spreadsheet

I currently use the good spreadsheet included in StarOffice. I am a very heavy spreadsheet user, so here are some other promising programs I keep my eyes on.

gnumeric

(in X terminal) Nice spreadsheet, part of GNOME, included with standard RH distributions (RH6.0 or higher). Although still fairly incomplete and sluggish, it is already quite usable  Gnumeric is under heavy development and definitely has the potential to become really great in the near future--it already has a lot of built-in functions, but its printing is unreliable--major pain.

kspread

Kspread is another highly promising spreadsheet. It is part of the KDE project to be integrated with the KDE2.0, most likely you don't have it on your system and I would not advice you to try to install it--it requires next-generation KDE libraries (on which KDE2.0 will be based) and you can screw up your KDE if you try to install these with your KDE1.x version). So far, kspread is not included with RH6.2 or Mandrake 7.0.

Both gnumeric's and kspread's file format is xml (the already standard, next-generation, enhanced html). This file format is definitely good news if you ever experienced problems with MS-Windows-based spreadsheet file formats.

Databases

If you are a database person, you will be pleased to see that Linux is very well covered in this area.

postgreSQL is a high-powered database available on Mandrake and RH CD (free,unrestrictive BSD license).

mySQL http://www.MySQL.com/  GPL database, simpler and easier than postrgreSQL.

There are also commercial databases which are free for personal use, e.g. Sybase for Linux ( http://www.sybase.com:80/sqlserver/linux/aselinux_install.html ) and Interbase ( http://www.interbase.com/downloads/products.html).  There is also Oracle for Linux: http://platforms.oracle.com/linux/index_lin.htm. For an Oracle-Linux howto, see: http://jordan.fortwayne.com/oracle/index.html

CAD

QCAD (GPL): http://www.qcad.org (simple but very useful)
OCTREE (free for non-commercial): http://www.octree.de/html/frames/eng/f_octree.htm
VariCAD (proprietary commercial): http://www.varicad.com/
VARKON (LGPL): http://www.varkon.com/
Microstation (proprietary): http://www.microstation.com/academic/products/linux.htm--the academic edition of Microstation includes the Linux version of their excellent CAD system (better than AutoCad).

Web browsers: Netscape and Lynx

You probably have installed a 4.xx version of Netscape during your RedHat installation. To run it, try (in X-terminal):

netscape

If you didn't install Netscape, you may want to put your RedHat CD into the CDROM, mount it using, for example (as root):

mount -t auto /dev/cdrom /mnt/cdrom

and then start, from X-terminal:  glint (for RH5.2) or gnorpm (for RH6.0) or kpackage (for RH6.1) to browse the available packages and  perhaps install netscape from your RedHat CD.  If you prefer to do the installation from from the command line, try, after mounting the CDROM:

cd /mnt/cdrom
cd RedHat/RPMS
rpm -ivh netsca*

Netscape is a very good browser, with the same look, feel, and power as Netscape for MS Windows, so you will have no problems navigating it. On the dark side, Netscape sometimes crashes (just disappears from the screen, no damage done, you have to restart it). Also, in some configurations, Netscape does not like to be be run without a connection to the Internet (depending on your configuration, Netscape can take up to a couple of minutes to figure out that there is no connection).  Netscape version 4.72 seems to be much better than previous versions, so if you are having problems you may consider upgrading.

Take your heart, once tuned-up, Netscape runs quite well (I use it all the time). Mozilla (the already famous, revolutionary offspring of Netscape) is under way so hold your breath :-) .

If your Netscape version lower than 4.72 is too buggy to you, you may want to disable Java ("Edit-Preferences-Advanced"). This improved the Netscape reliability tremendously on my system. Additionally, you may want to disable the automatic checkup for new mail (solved the "freezing" problem I used to experience when working off-line), empty your mail "trash" bin, compress the mail folders on regular basis, and disable Javascript. After doing all of this, my previous versions of Netscape worked quite nicely.

If your Netscape crashes and on a subsequent re-start complains about the presence of a lock file,  it might have left a lock file in your home directory. Just quit any instance of Netscape that you might be running and delete the "lock" file from the directory /home/user_login_name/.netscape:

cd ~
cd .netscape
rm lock

If your ISP connection is really slow, you may prefer a text-based browser:

lynx

which is a real piece of art and does not have any problems whatsoever. Don't expect it to look as fancy a GUI-based browser though--it is text-mode based.

Another choice of a Internet browser is your KDE help utility (click on the "book with the lightbulb" button on your K-bar). This is a simple html browser so if you are connected to the Internet (e.g. using your kppp), you can browse almost anything using this utility.

To compose html pages, I use Word Perfect, StarOffice or Netscape (WYSiWYG view) and WebMaker (code view).