I'm often asked "what's the best language to use to write xxxxxx", where xxxxxx is a description of an application.

It might be that I can give a list of languages that are technically excellent to do the job, but there are circumstances where a language that's merely capable of doing a good job should be chosen.    For example, if you're already a heavy user of language k, that should probably be your first choice for new jobs - both those that k is excellent for, and also those which it is suitable for, even if you wouldn't normally consider telling someone to learn k to do this new job.  

Another situation where you should go for a language that may not be, technically, the best relates to the availability to you of support.   If you work in an environment where everyone else is writing Java, why go out and learn Tcl and plough a lonely furrow?   Much better to use Java if you can; there will be colleagues there to assist and advise you as you learn your way into the world of programming.

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