Macintosh / OS X links

OS X hacking tools
KisMAC passive stumber for OS X
The X Lab
Quicksilver intro

Unix links

A Byte of Vim: excellent Vim manual
Linux command reference
10 must-have unix tools
Introduction to Linux
How to author video DVDs w/menus using Linux only
Simplify data extraction using Linux text utilities

Math / Science links

Hyperphysics: online physics tutorial
Matrix & Quaternion FAQ
BibFinder: Computer Science Bibliography Mediator

Programming / technical links

The TeX FAQ
Low-level virtual machine (LLVM)
Best Vim Tips
Meld visual diff and merge tool (human readable version of diff)
Non-Uniform Random Variate Generation: a great free book that tells you how to do just what it says
Colt: high performance scientific computing for Java
Description and documentation for LaTeX packages
HTML 4.0 Reference
Princeton 3D Model Search Engine
High-resolution VCD/SVCD stills on the UNIX command line
matlab-like plotting library for python
processing: a language for creating images and animation

Robotics links

Android world
ODE: Open Dynamics Engine
Trinkle's survey of multibody dynamics software

Miscellaneous

Can't decide where to eat? Let the cube decide.
Free high-res wallpaper
Urban Dictionary
How to get files off of your iPod
Ron Azuma's guides for the Ph. D. student
Open Source Web Design