New answers tagged web-safe
Re-posting as answer here just in case someone misses the comment. I've always used Liberation Sans for web, because it's one of the fonts that render the best with @font-face:
The good one is Neue Haas Grotesk, but if you need a typeface only for headings I can propose my own typeface :) Take a look on this image.
The most common/closest 'alternative' to Helvetica is likely Arial, which is already installed on most computers, so you don't even need to use it as a web font.
Top 50 recent answers are included