Awhile back when Go was fairly new I played around with it a bit using Vi or Notepad++ as an editor, at the time there were no IDE's available. Now I'm planning to do some work with it and after a quick search found there are several options. After that I took a look at SO and found all the questions regarding Go IDE's were dated.
So, now that there are some options it's time for me to ask; What IDE would you recommend for Go? Why? I don't care which OS(s) it runs on but please make a note of which. Basic feature bullet points would be appreciated though not entirely necessary.
There's a lot of complete options, and github.com/nsf/gocode is a helpful part of that. The go src includes binding for vim (what I've been using for the longest) and emacs. Ctags and go seem to play well together with CtrlP and tagbar can be augmented to work as well if that's your thing.
I recently started using sublime text 2 and the plugin GoSublime. Code completion, auto format code, quick bindings for running pkg unit tests out of the box, lots of nice things to be productive.
If you already have a vim setup you enjoy, then roll with that b/c it works great. I'm rather impressed with sublime text myself and plan to (try and) use it going forward.
I doubt anyone can answer this for you, as it is a very personal thing. So to that effect, here is a listing of the currently available editors and Go-related plugins.
I don't know if it is complete, but it will at least get you started.
Edit: Personally, I use Gedit for everything. It has facilities to hook up whatever external tools I need, although I rarely use them. The only Go-related thing I do use is the syntax highlighting. When it comes to Go, I find there is not much need for a full-blown IDE. Languages like C#, C++, Java are just not productive when used without a whole IDE framework built around it. Go does not have this problem.