Seconded. "A Tour of Go" didn't really stick until I actually started writing code by following Learn Go With Tests, and then it clicked. I had to learn it because I got put on a Go project at work and needed to get comfortable with the language over a weekend -- and after doing Learn Go With Tests I was ready to hack on production code come Monday (with some supervision, hah).
And it’s been kept up to date through go versions and new content has been added to it over the past year.