While Go becomes faster and more scalable (if you don't yet tried it, don't miss An Online Tour of Go), our team was working on the AddressSanitizer (ASan) - a fast memory error detector for C/C++. The tool is really fast, a typical slowdown is only about 2x (while with, for example, Valgrind/Memcheck we observe slowdowns of 20-50x). And the speed is a real game changer here - we build Chromium with ASan and then do interactive browsing, or execute thousands of randomly generated tests and then do dichotomy reduction of crashing tests. It's interesting to observe how the tools spreads basically w/o our efforts, for example, here somebody writes how to build Firefox with ASan, and here is an interesting story of "ASanified" Perl.
Here are some concurrency-related links:
Concurrency Kit provides a plethora of concurrency primitives, safe memory reclamation mechanisms and lock-less and lock-free data structures designed to aid in the design and implementation of high performance concurrent systems.
Chasing state of the art: Java synchronization algorithms.