Proxima Sans
Proxima Sans (1994) stradles the gap between typefaces like Futura and Akzidenz Grotesk. The oblique styles are optically adjusted, not just slanted versions of the roman.
Proxima Sans features a complete character set and extensive kerning tables.
In 2005, Proxima Sans was expanded and completely redesigned. The new 42-font family is called Proxima Nova and can be seen here. Proxima Sans will continue to be available for those who cannot use OpenType fonts, but Proxima Nova is a better choice for everyone else.