Now, for a Black Belt language, THE one I miss, is APL. It was so beautifully cryptic, compact, fast, and mathematically powerful as well, David. The other kanguage I miss, a Green-belt-level language interms of power and ability to write in it is called ATLAS.
Although I've been doing C++ for 11 years and C for 5 prior to that, I'm still learning C++, and occasionally pull out my K&R book for something or other. The most recent development in C++ that gives it even MORE muscle is the STL suite, now an adopted part of the language and gaining maturity. STL provides, as libraries, data management and manipulation tools it once took weeks and even months to write and debug.
I like to develop code with System International (SI), David, as well. But there's no valid and useful SI implementation in all of Intel land. As you know, David, SI is merely the system of units attached to code and prevents one from designing and writing obtsuse and obscure errors into his code. For instance, with SI it is impossible, say, to mix units of any kind that are not supposed to be combined together, say mix transmission fluid with antifreeze and gasoline with motor oil because one actually has to write 5 gallons gas times 3 quarts oil to attempt to put them together. The compiler happily slaps both wrists as it adamantly says "No, stupid! You can't do that. Can't you tell the difference."