Font: Arial

When to use it: Arial has a modern feel, but is more compact than Verdana. Useful for designs where space if limited.

Often thought of as Verdanas ugly cousin, Arial has a much tighter feel to it which arguably makes it harder to read. It is a very clear font though so you'll still see it used a lot. Sometimes a certain design will just feel better using Arial as opposed to Verdana.

Try the following CSS:

div {
  font-family: Arial, Verdana, Sans-Serif;
  line-height: 1.8em;
  word-spacing: 0.2em;
  font-size: 76%;
}

The results:

Font: Trebuchet MS

When to use it: When you need a slightly quirky feel to your text

A sans-serif font that really gives a distinctive offbeat look to text, while still maintaining very good screen readability. Trebuchet MS is now becoming a very popular font with designers who want their sites to stand out from the crowd.

Try the following CSS:

div {
  font-family: 'Trebuchet MS', Verdana, Sans-Serif;
  line-height: 1.8em;
  word-spacing: 0.1em;
  font-size: 80%;
  letter-spacing:0.01em;
}

The results:

Is that it then?

Well no, there are other popular fonts out there that people use, but the ones above are probably the best for day to day use. Remember though, that choosing the right font is only the first step in crystal clear readable type. There's a lot more to think about, and factors such as margins around text have a huge impact on the overall readability.

And of course you've got to have something worthwhile to say as well!