TeX support

By the way, when text.usetex is set to True, could one

    > imagine to be able to use string arguments to the mpl
    > text routines whithout that leading 'r' ?

The need to use raw strings is a python requirement and not a
matplotlib requirement

s = 'this is \nu'
print s

this is

backslash has a special meaning to python, and the only way around
this is to either hack your own python shell (eg modify ipython),
quote the slash (eg use \\) or use a raw string. Of course, if your
TeX expression has no special characters (eg no backslashes) then you
will not need the raw string quote.