I'm extremely happy with nsf's gocode [1] adding auto-complete support to Sublime Text and Vim. It's quite nice. Go, itself (from `hg`), has syntax support for vim and (I think) an emacs plugin. There's also a Goclipse modified Eclipse install which I don't know much of anything about.

There are others, [2]

I mean, there certainly isn't a complete equivalence of Eclipse for Go (yet?).

[1]: https://github.com/nsf/gocode

[2]: http://go-lang.cat-v.org/dev-utils http://go-lang.cat-v.org/text-editors/ etc, etc