There are over 600 Google web fonts to choose from which is a good and bad thing - the good being there are so many good ones to choose from, the bad being having to sift through them to find the perfect one.
When you're running large scale sites that get hundreds of thousands of visitors a month, paid services like Typekit just aren't worth the money. You're much better off saving thousands of dollars by using Google web fonts.
Honestly, around 60% of Google web fonts are just downright rubbish (sorry to hurt anyone's feelings!), so I wanted to create this post showing the best fonts I've come across. These are fonts I've used myself in projects and themes and recommend to any web designers. I may have missed some other brilliant fonts, so do mention any other great ones in the comments.
Open Sans is a no brainer really. It's one of those universal fonts like Arial or Helvetica. It works in most situations, comes in many different weights and is legible in many different sizes.
Source Sans Pro
Similar to Open Sans and is very universal, can work in most situations. Comes in many different weights. Was created by Adobe themselves.
The system wide font used in Android. Created by Google and of course comes in an array of different weights. It's great for headers and body text.
Easily one of my favourite fonts. It's probably my most used font when it comes to titles and headers - it's perfect for those uses. It's a great free alternative to the paid fonts Proxima Nova and Gotham. It's not a great font for body text though.
A brilliant serif font with a very classy and traditional look. It's perfect for large amounts of body text. Great alternative to the very commonly used Georgia.
Great font for those who love large headers or the vintage look. Definitely not a good font for a body text though so don't be silly and use it for that!
A modern slab serif font. Great for titles and headers.
This list will be updated with new fonts so make sure to come back!