Sparkfun – The best source of all things electronics. On top of that, they provide the internet’s best library of tutorials surrounding the products they offer, and a fantastic beginner’s kit for the Arduino platform. Be sure to subscribe to their YouTube channel for the New Product Post every Friday, to see what new items they’ve invented / adopted.
Robotshop – Another great resource for electronics. They specialize in robotic parts and have a huge variety of servos. For my fellow Canadians, they carry many of Sparkfun’s products for those of us north of the border.
Abra Electronics – A huge variety source for electronics. They too carry Sparkfun products in Canada, but also offer many of Adafruit’s products and give great discounts for educational programs.
Adafruit – Another awesome entity which develops its own products and provides thorough assembly and programming tutorials as well.
Super Bright LEDs – Want LEDs that are brighter than the sun? You can come close with the products carried here! The brightest and biggest variety of LEDs I’ve found on the internet.
Mouser – This is the only place I go for my surface-mount components. Super-fast service and delivery with a massive selection of components.
Shapeways – My source for all 3D printing needs on the web.
Sparkfun Inventor’s Kit – The recommended starting point for every beginner in both programming and electronics.
Arduino Uno – When it comes to programming and prototyping, there is nothing better in my opinion (Sparkfun Inventor Kit may include a “Red Board”, but it functions nearly identically).
Arduino Pro Mini 3.3V – Once you’ve mastered creating your circuit with the Arduino Uno, this version of the Arduino is a tiny version with the same capabilities, and can help compact your designs without losing functionality or modifying your code.
Lithium Polymer Battery (850mAh) – These batteries are the same as you would find in a cell phone, which provide high power output in a slim form factor. They are rechargeable, affordable, and come in a variety of capacities and sizes. However, in most cases only two batteries can be shipped in a single order.
Hitec HS-422 Servo – A super-strong and very affordable servo with a standard size case. Highly recommended.
5050 SMD Cool White LEDs – If you have a PCB with this footprint, these LEDs are actually not too difficult to hand-solder to the board. They are very slim and provide a lot of light. Available in many different colours from Super Bright LEDs.
ADXL335 Accelerometer – A fantastic choice for all tilt-monitoring purposes.
Autodesk 123D / Inventor – Arguably one of the easier programs for designing 3D models which you intend to print (or not).
EagleCad – A simple but extensive PCB (printed circuit board) design software with a solid parts library. Download the Sparkfun library for even more parts.