[vezzy-fnord]

I'm not entirely sure, but I believe Go is basically a continuation of Rob Pike's vision in terms of how computing should be in general. (Plan 9, acme, rio, procfs, etc.) It's the spiritual successor to Limbo, which itself was the successor to Newsqueak. They basically extend upon the general model of C, but add things like built-in concurrency (inspired by CSP), conservative garbage collection, type checking and so forth. They also aim for simplicity and removing complicated features (see also cat-v.org and "harmful software" to understand the philosophy).

As for C++, Java and so forth, popularity is no indicator of quality. That and Smalltalk/Smalltalk-esque languages had rocky starts, including difficulty of acquiring development environments and performance overhead.

EDIT: Concerning Objective-C, it's pretty tough to work with it outside of an OS X-related environment, because of the lack of essential libraries. There's GNUstep, which tries to fill in the gap, but it remains very behind and it has very little development going for it.