Here is a short list of some really useful software (for Windows - I have used these under Win 98, NT, 2K, XP, Vista, and Win7).
The Semware Editor (Who needs a word processor?)
(And to spell check your documents, try
MicroSpell - there is no
spellchecker nearly as efficient IMHO.)
TEX
(Type processing the way it's meant to be.
Word-processors
are stupid and inefficient)
[LaTeX is pretty cool.]
TeraTerm (A really smart ssh/telnet program.)
PuTTY is also excellent
Opera (The fastest, best web browser available - beats Internet Explorer.)
If you're nostalgic for Netscape, give
Mozilla or
FireFox
a try - or if Google's your friend, try
Chrome.
For a really small (Windows only) browser, try
Off-by-one.
Proxomitron (Kill those annoying ads when you are browsing the
web.)
MailWasher (A powerful email checker with effective spam
elimination. The same folks also provide an excellent mail filter with
their program Benign; it eliminates viruses, trojans, bugs, etc from your
email before you read it.)
Core FTP (lite)
(A simple convenient way to ftp files.)
For command-line fans: NcFTP is unbeatable.
Leech FTP - no longer supported by its author, but still an excellent
program. Another oldie: Free WS_FTP (the current
version is no longer free, but this older version is.)
XNews (A free but excellent news reader.)
KeyText (Keyboard macro program to automate Windows tasks.)
Info-Zip (Zip and Unzip for
all "platforms" - used so often you tend to forget you have it after a
while!)
IrfanView32 (General purpose graphics utility - one of the best, and
it's free.)
VLC (General media player - better than WiMP!)
Some older programs (I don't use them under Win7):
Magellan Explorer (A file
manager that illustrates what "My Computer" really should be!)
PaneKiller (A replacement for the Start menu on the Windows
taskbar.)
World Time (Keep track of time in different time zones, alarms,
stopwatch, ... - if it is about time, this is your program.)
[Get the
current "stable" version here!]
(If you want a "lighter" program that does less, but still gives you
different timezones, try
ClockRack from PCMag.)
Desktop Manager
(Give yourself 4 or more desktops, each with its own display settings.)
DialUp Networking Monitor (See your dialup stats and monitor your
connection.)
UCalc (A small scientific calculator and graph plotting program -
fast and useful.)