I earned my living between 1988 and 1997 developing and being a mentor using C++. I usually argue against using C++, a language that offers superb runtime performance (speed and memory utilization) with the penalty of greatly increased development costs.
For most applications, it is less expensive to optimize for developer productivity. In my decade of using C++, with hindsight, the only projects that needed the performance of C++ were a commercial product for Windows 1.03, some VR work for SAIC and Disney, work on two Nintendo video games, a real time expert system for PacBell, and a PC racing game. All other C++ projects could have been done with more economy and effectiveness using other languages.
I used to error on the side of staying current with too many programming languages, although in the last few years I have invested heavy time in only three: Ruby, Java, and Common Lisp. Even though I find C++ development to be less fun, slow, and sometimes even a little painful, I am considering replacing Common Lisp with C++ in my small set of 3 languages that I am willing to invest heavily in. This Benchmark game of C++ vs. SBCL Lisp is one reason for this (possible) decision. The other reason is that I find Ruby to also be very good for quick prototyping and fast agile development, and even though the runtime performance of Ruby is very poor, it seems like the combination of Ruby + Java + C++ covers a wider range of application development than the combination of Ruby + Java + Lisp. In other words: Ruby gives me a lot of what Lisp does and I feel like I need one agile scripting language in my programming language toolbox.
Sure, "the best tool for the job", but I like to also consider the costs of not totally mastering the tools that I use in my work. This is why I have given up (for serious work) some great programming languages like Python, Smalltalk, C#, and Prolog.