Fundamentals

What's an AVR?
Getting Started
gcc-avr and avr-libc resources
Your first program for your AVR microcontroller
AVR Chip comparison and benefits versus other microcontrollers
What you need to order from digikey for getting started with AVRs
Using the demo version of Bascom AVR. It's limited to a 4KB program, but otherwise fully featured.

Source Code Library

"AVR Mirror" -- The "Hellow World" of embedded programs
How to use the AVR's builtin functions: Timers, PWM, RTC, ADC, SPI, etc.

Hardware for your electronics workbench

AVR Development Boards and chips
Workbench Essentials
Misc. Electronic Parts
Other useful but expensive items

Project Ideas

Simple Reverse Engineering Tips
The Dallas Semiconductor One Wire protocol and devices
Interfacing to a DS1822 temperature sensor, with source code
udelay: A microsecond accurate, nonblocking delay loop
A logging temperature sensor
Controlling Bipolar Stepper Motors with a ULN2003
Using a 74HC595N serial shift register latch with an Atmel AVR
Using an external serial eeprom with an Atmel AVR

Design your own PCBs

Places you can send a design file to, and get a board n weeks later.
http://pcbexpress.com
http://expresspcb.com (and their own Free Layout SW)
http://pcb123.com (also their own Free Layout SW)
http://www.protoexpress.com/
http://www.4pcb.com (They have a free design checker too)
http://www.pcbfabexpress.com/

These 2 have cheap single-board prices.
http://www.batchpcb.com
http://www.olimex.com/pcb/index.html (taking month of August off, probably for a big job)

See also http://opencircuits.com/PCB_Manufacturers (consider merging these lists)

Or, finally, you could hand-wire a prototyping board. Olimex boards look to be the cheapest.

PC Software

Software for Linux users
Software for Windows users
Software for Apple users

Resources & Web Sites

DigiKey for all your digital parts needs.
Mouser if you can't find it on digikey.
Triangle Tool for anything industrial, like gears & motors.
HSC Electronic Supply for one-offs, single lots, wire, boards, and other fun cheap stuff.
Weird Stuff if you want something to take apart and see how it works.
Jameco even has in-store pickups in the Bay Area.
McMaster-Carr has just about any sort of gear, motor, or mechanical device you could ever imagine.
AVRfreaks is a large AVR user community.
So what is the relationship between the http://wiki.avrfreaks.net/ wiki and the http://avrwiki.com/ wiki?