It's not the gap between my teeth, but a:

Monospace typefaces in which every character is the same width (usually, font width is variable; the "w" and "m" are wider than most letters, and the "i" is narrower). The first monospaced typefaces were designed for typewriters, which could only move the same distance forward with each letter typed. Their use continued with early computers, which could only display a single font. Although modern computers can display any desired typeface, monospaced fonts are still important for computer programming, terminal emulation, and for laying out tabulated data in plain text documents.  - Wikipedia

On today's Digg feed, there's a great piece article, Visual Comparison of 18 Monospaced Fonts. If you're a lover of good typography, it's a great read. If you do a lot of code reading, it could be your lifesaver. If you are a "designer" who doesn't know what kerning is, then this is definitely NOT the article for you.