For intense number-crunching i\'m considering using fixed point instead of floating point. Of course it\'ll matter how many bytes the fixed point type is in size, on what CPU i
Use fixed-point when the hardware doesn't support floating-point or the hardware implementation sucks.
Also beware when making classes for it. Something you think would be quick could actually turn out to be a dog when it comes to profiling due to (un)necessary copies of classes. That is another question for another time however.