Your font choices are extremely limited.
See
Common fonts to all versions of Windows & Mac equivalents (Browser safe fonts) - Web design tips & tricks
1. You have to accommodate both Windows and Mac OS X users.
2. You can only rely on default fonts. Just because I have a $1900 Helvetica set does not mean that everyone does.
3. The font needs to be appropriate for the business. For example, a tool & die company would never use Comic Sans as it says they are not serious.
4. The font must be easily read on a computer screen. Some fonts (e.g., Times Roman) were designed for paper and are not as well suited for the lower resolution quality of people's monitors.
So, your font choices are limited to the
intersection of the four sets above.