I am always drawn to pear shapes - there is something so appealing to my eye! Maybe it's the feminine shape... but I really love them! Have purchased a few coloured stones - not all good choices, mind you! - but they all seem to be in the pear shape! Morganite, aquamarine, amethyst, several sapphires... I sense a theme
No favourite, really, just anything as long as it looks great. I don't know why but I am less particular about shapes when it comes down to pendants. Oval, round, cushion, trillion, rectangular, pear, or even fancy outlines will do.