On one hand, using multiple fonts in a print layout can open you to a world of creativity. On the other hand, if you use too many fonts (or if the fonts you choose don’t work well together), you don’t end up with creativity; you end up with a mess.
Type often obeys the engineering law “form follows function”. That is, a typeface should be appropriate to what the typesetter designed it to do. At the same time, that form needs to be aesthetically pleasing. The basis of good typographic design is balancing the two.
Bell Gothic was designed in 1938 to improve the legibility of phone directories, as well as provide economy of space.
Frutiger was designed to make airport signage easy to read from a distance.
Courier inspires a sense of nostalgia.
When choosing a font, choose a font appropriate to the task at hand. Think of fonts like clothing. What we wear should be appropriate to the weather as well as to the context (formal versus casual), but also be attractive. We normally don't dress up in our most extravagant attire everyday, just when the occasion arises.
Smashing Magazine wrote a great article titled "What Font Should I Use? 5 Principles for Choosing and Using Typefaces". Pulling from there, the author wrote:
"My favorite piece of clothing is probably an outlandish pair of '70s flare bellbottoms that I bought at a thrift store, but the reality is that these don’t make it out of my closet very often outside of Halloween. Every designer has a few favorite fonts like this — expressive personal favorites that we hold onto and wait for the perfect festive occasion to use. More often, I find myself putting on the same old pair of Levis morning after morning. It’s not that I like these better than my cherished flares, exactly… I just seem to wind up wearing them most of the time.
Every designer has a few workhorse typefaces that are like comfortable jeans: they go with everything, they seem to adapt to their surroundings and become more relaxed or more formal as the occasion calls for, and they just seem to come out of the closet day after day."
Showy faces aren't taboo, they just ought to be used sparingly. More often than not, type faces need to be standard, practical, and most importantly, legible.
Some popular "workhorse" fonts include Helvetica, Garamond, Futura, Frutiger, and Rockwell.
Within a document, sometimes you wonder if you should add a second face or not. More commonly, making the headline thicker, with more weight, greater size, and sometimes even in an accent color, do the job perfectly well. However, sometimes adding a second type is what's needed. Smashing Magazine had a great insight regarding this: "keep it exactly the same, or change it a lot — avoid wimpy, incremental variations".
While it’s tempting to think that no one really pays close attention to fonts, there is often a subconscious visceral reaction to bad type, not unlike the subconscious reactions that we have poor color combinations or out-of-date clothing.
Understanding how font choices affect the perception and reception of documents is one of the crucial elements to good design. You should not treat it lightly. If you need help, just ask.