If you are going to make items different, make them very different. If you want people to read continuous text, don't use contrast, including links. Create a focal point, through contrast. A proportional font is one that allots different amounts of space to each character, based on its design. Helvetica, Times, and Arial are examples of proportional fonts.
Web browsers use a proportional font for the majority of text in the web page.
In general, proportional fonts are easier to read for large bodies of text. Fixed-width fonts are designed to allot the same amount of horizontal space to all characters in the font. Courier and Monaco are examples of fixed-width fonts.