Here is a list of some of my favorite GIS and cartography resources.
Part of the Stackexchange family of Q & A sites, this is a great place to get your questions answered on topics ranging from general methodology and principles to specifics of various software platforms. Some of the topics I post about on this blog were figured out with the help of GIS Stackexchange.
The Open Source Geography foundation is caretaker for a family of powerful web and desktop geography tools, including Quantum GIS, GRASS GIS, and Opticks. Their site is your one-stop shop to getting started with free and open-source GIS software.
The System for Automatic Geoscientific Analyses (SAGA) is a very powerful free and open-source GIS analysis package. The interface is a little bit intimidating, but the range of analysis tools available makes it well worth learning. I find that it performs many tasks faster than ArcGIS, and the upcoming version 2.1 promises to implement multi-core support and full 64-bit processing, so things should only get faster. As a bonus, many of the tools include primary literature references for the methods used, which is a boon for researchers.
Spatialite is a light, fast DBMS with spatial functionalities. It’s a great way to get started with spatial SQL, which can sometimes solve problems that are difficult or impossible to solve with other geoprocessing tools.
List of useful resources for learning Python as it pertains to GIS.
Incredible resource from master cartographer Tom Patterson. Includes data, articles, and tutorials on advanced cartographic techniques.