I think the hardware has 18-bit DACs. So- no, period, forever, the end, if I'm right about that.
Now, there are also the arguments that take into account the physics of dynamic range, the ear, noise floors, and blind A/B tests with properly mastered and dithered 16/44 material, and those who feel that 24-bit is important for headroom in mixing and pre-mastering situations, but... that is another discussion.
Personally, I recommend reading things like
http://xiph.org/~xiphmont/demo/neil-young.html and
http://www.drewdaniels.com/audible.pdf to help you feel better about only having an 18-bit DAC...