Released in 2005, Proxima Nova is a hugely-popular typeface designed by Mark Simonson. It is often described as a hybrid of Futura and Akzidenz Grotesk, combining a geometric appearance with modern proportions. In my opinion, Proxima Nova’s use on the web is so ubiquitous that it is starting to feel a little overused. It’s still an excellent font though, so there’s a reason for its popularity.
If you are looking for an alternative to Proxima Nova, I recommend checking out Gotham and Avenir. I think Garamond would make a nice font combination with Proxima Nova.