Tutorials
Lynda dot Com - Affordable video tutorial website. Great resource!
Smashing Magazine Best-of-Illustrator-Tutorials - A neat list of tutorials for Adobe Illustrator.
Downloadable Resources
Illustrator Brushes at DeviantArt - Plenty of cool brushes and other items. You might also need help installing brushes.
Third-Party Illustrator Plugins - Adobe has linked to lots of neat plugins you may need for special projects.
Inkscape
Inkscape is an incredibly capable Free-software package like Illustrator. Though it's not quite as comprehensive, the fact that it can be put on a USB disk to carry around with you is really helpful if you do a lot of designing and may not always have access to a computer with Illustrator on it. There are plenty of nicely-made free video tutorials for it as well.
Inkscape uses the SVG graphics standard, which is going to become very popular in the years ahead.
Raven (Part of Aviary)
Raven is an online vector drawing program that's similar to Illustrator. Though it lacks a lot of advanced features, the fact that it is integrated with the other Aviary design tools is a big advantage. It can be used wherever you have an internet connection. There are tutorials and galleries on the Aviary website. Aviary will probably cost money to use in the future, but it should be much cheaper to use than Adobe tools, which is a big plus for many people.
Note that these tools are not necessarily meant to compete with Illustrator across the board. You may find it most helpful to use them first, then ask yourself if they are useful to you, rather than doing it the other way around.
Finally, check out the depth of Illustrator tutorials available at Vimeo.
Color Websites
Colr.org - Develop schemes from photos, websites, and view shared color schemes.
Colr Pickr - Find Flickr photos that match any color.
Color Schemer - Browse color schemes that people have created and shared.
Color Scheme Designer - Use color tools to generate different color schemes, with the ability to view them as color-blind people will see them, or see how to make website layouts with them (bottom-right menu).
COPASO color generator - Another one with some advanced features.
Adobe Kuler - Adobe's color scheme tool.
Flickr Color Scheme Generator - Search for a phrase (like "hot air balloon") and watch as it finds photos and develops color schemes based on them.
Desktop Color Software
Color Cop - Desktop color picker tool for Windows - very handy.
Hex Color Picker - Macs come with a built-in color picker, but this one is a good addition to it.
GColor2 - Linux (Gnome) color picker tool that lets you save your colors for future use. There is also a KDE application called "KColorChooser"
Some people get really, really picky about typography. Complaining about the font used on a gear shifter seems a little extreme, but Mercedes do spend a lot of money on typographic design - even to the point of having superstar typographer Kurt Weidemann create the Corporate font trilogy for Mercedes Benz.
Like many organizations, Stanford University has made a set of design guidelines for Stanford publications. Included are a set of typography guidelines that are interesting to read. SF State University has also prepared a similar page; you'll notice that both schools allow designers to fall back on Times and Arial because these two fonts are guaranteed to be found on any computer.
Use a tool like Esperfonto to help make decisions about which typeface to use.
If you would like to explore some free fonts, take a look at a site like Dafont. If you're interested in broadening your horizons and looking into professional fonts, check out MyFonts.
Try to avoid overused fonts.
Aanother site lists the seven "worst" fonts, by which they mean "inappropriately used".
Some graphic designers were asked, "if you could only purchase six fonts, which would they be?"
A "Lorem Ipsum" text generator can come in very handy for generating "dummy" text.
Short letterpress & typography documentary
Have a favorite tool or design-related link? Let me know about it!