Times New Roman
Times New Roman is a Windows serif font that looks like something you'd see in a newspaper or magazine. It's specially hinted for easier reading on-screen, but Microsoft's free font Georgia is really a better typeface for the screen.
Mac users can download it for free...
  Download Times New Roman for Mac [466 KB]

Times
Times is a Mac serif font. It's similar to Times New Roman, but it isn't as carefully designed for on-screen viewing.

Georgia
Georgia is a Microsoft's serif face. It's much easier to read on screen than other serif Web fonts because it was designed for the screen. Georgia has excellent italics that are easy to read and attractive.
You can download Georgia for free...
  Download Georgia for Mac [347 KB]
  Download Georgia for Windows [383 KB]

Arial
Arial is a Windows sans serif font that has a streamlined, more modern look, but isn't easy to read on screen because it's narrow and can look very light in smaller sizes.

Helvetica
Helvetica is a Mac sans serif font similar to Arial.

Verdana
Verdana is an extremely easy-to-read sans serif font that's included with the Internet Explorer.
Mac users can download it for free...
  Download Verdana for Mac [293 KB]

Tahoma
Tahoma comes with Microsoft Office and is almost identical to Verdana.
Mac users can download it for free...
  Download Tahoma for Mac [215 KB]

Comic Sans MS
Comic Sans MS is a sans serif font that's included with the Internet Explorer. It's informal and friendly, which is great for some Web sites, but not professional enough for others.
You can download it for free...
  Download Comic Sans MS for Mac [179 KB]
  Download Comic Sans MS for Windows [240 KB]