I don't consider myself a designer in the least, but these are my go to fonts:

Sans-serif:

Myriad Pro/Avenir (Very similar, to me at least. Should probably have at least one set).

Avant Garde

News Gothic

Code Pro

Serif:

Rockwell

Stempel Schneidler

Stone Serif

Go, therefore, and download Source Code Pro, and install it on thy machine, and make it the font in thy text editor. For it is the holiest of holy monospaced fonts, and shall make thy eyes moist with its beauty, and shall wipe the Monaco-ites and the Courier-ites and the Menlo-ites from the face of the earth.

Seriously, though, that font is awesome. I use it in all my assorted text-based tools (terminal, text editors, IDEs, everywhere).

Other awesome fonts (that are also free) are the ones always near the top of Google Fonts: Open Sans, Lato, Roboto, and Raleway are some of the more popular. I like Raleway in particular.

Great! Thanks so much!

This is a loaded question. There are some very solid traditional fonts that have stood the test of time, many of these such as (but not limited to):

Serif Didot, Garamond, Sabon, Clarendon, Bembo, Georgia, Baskerville, Paletino, Caslon, Benbo, Times

Sans-Serif Gill Sans, Helvetica, Avenir, FF Din, Futura, Frutiger, Lucida Sans

Some helpful posts I would recommend checking out would include:

• http://www.creativebloq.com/typography/fonts-for-designers-2131830
• http://blog.spoongraphics.co.uk/articles/25-classic-fonts-that-will-last-a-whole-design-career
• http://www.vectordiary.com/fonts/30-classic-fonts-every-designer-should-own/
• http://www.pencilscoop.com/2013/10/20-best-new-font-foundries-every-designer-should-know/

Today with the introduction of digital fonts, there is almost no end to whats available. Many of the older fonts have been digitalised and re-created for computer use, or have inspired some new designs. One thing I would stress though when selecting a font though make sure that the family includes AT LEAST four styles Regular, Bold, Italic & Bold Italic as a minimum. This will also mean that you're not using your text editors faux bolding or oblique to badly render the type with horrible consequences.

Also keep in mind that some fonts have been specifically designed for screen use, such as Verdana, while most traditional fonts were designed with letterpress printing in mind. When considering a font, I would always suggest looking into the fonts history, as this will often help understand what it was initially designed for, and may help influence you decision to use it.

This might also prove useful. http://www.noupe.com/essentials/icons-fonts/a-crash-course-in-typography-the-basics-of-type.html

Also with the proliferation of FREE fonts, do be cautious, while there are some amazing fonts available, there are also some incomplete/bastardised ones out there. Google fonts is a great resource, as well as http://www.fontsquirrel.com while many of the tried and tested traditional choices will cost money.

When looking to purchase good quality font families I would suggest checking out:

• http://www.myfonts.com
• https://www.fontshop.com
• http://www.fontspring.com

I hope this helps.

Stumbled across this just now. Well worth considering getting hold of the top 10 on the list if you're serious about Typography. I've read another article by the same name, and the list was very similar, with only small differences, this offers a pretty good guide based on the sale of fonts from FontShop, you'll also find a brief history of the typeface included.

The 100 Best Typefaces http://www.100besttypefaces.com

Failing that here's a good article.. http://justcreative.com/2008/03/02/30-best-font-downloads-for-designers/