Proxima Sans
Proxima Sans (1994; discontinued 2011) 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.