BASIC

So I asked /g/, but of course no one on /g/ actually cares about programming.

What sort of features might a good BASIC have?

None whatsoever, unless you are stuck with it, like a graphing calculator or something. If you want to learn all features you would need in IT/prog/ fields, I recommend you start with something more robust and multi-paradigm: Common Lisp (CL).

If you want to have something close to BASIC, try Pascal. But you best bet is to start with CL. Then learn Real languages like ANSI C, Scheme, Haskell, ATS, awk etc.