Links

Electronics - Worldwide
Proteus Design Suite - Schematic, simulation and PCB design software
MikroElektronika - Development systems, compilers and programmers
Proton Development Suite - PIC BASIC Compiler

Electronics - South Africa (Johannesburg)
Components
Electrocomp
Protronix
RS Components
Communica
Avnet Kopp
Connector Technology
CST Electronics
Mantech (Good for Power Supplies)
PCBs
Bosco
Trax
Labels / Membrane Switches
Membrane Switch Technologies
Electronic Touch Systems
Cables
Lapp Kabel (Strain-reliefs as well as cables)
Apex Cordset Technologies (Moulding)
Handy Technology (Moulding)
Transtronics
Batteries
SJ Andrews
Just Batteries
Contract Manufacturing
Microtronix
Transtronics (Hand assembly / through-hole)
LCD Displays
NuVision Electronics
Other
ACDC Dynamics

Windows Software Development
Microsoft Visual Studio Express
Inno Setup
Fugue Icons - Great Icon Kit

Graphics / CAD
Solid Edge Free 2D Drafting - 2D CAD
Inkscape - Vector Graphics
Gimp - Raster (Bitmap) Graphics
eDrawings - CAD Viewer
Google Sketchup - CAD

Utilities
7zip
PDF Creator
Windows OS Utilities

Manufacturing - South Africa (Johannesburg)
Material
Aluminium Trading
Gammid Trading
Maizey Plastics
Engineering
D-Tek - Laser-cutting too
Quick Turn Engineering
Small Parts
Skiffy
Capricorn Industries
Sandblasting / Powdercoating / Anodising
Astro Holdings
Packaging
Foampak
Dies Direct - Cutting dies
GearUp - Bags
Other
Carlin Medical Extrusions - Silicone moulding / extrusions

Adventure
Wolkberg Wilderness Area

Games
For expanding the mind (and because you need to have some fun too...)
Portal
Braid
World of Goo