I also gravitate toward purple ties. As long as the pattern is simple I think they are not too bright/flashy and go equally well with navy or grey suits as well as both light blue and white shirts. I have the dark purple/black fina grenadine, the English dot silk #2, and English stripe #33 (which may have been discontinued). I've also got 3 purples loaded on my wish list- plum thai rough silk, purple grenadine grossa, powder blue on dark purple flower silk.
Stealing this thought from scurvyfreedman today (although this may be too flashy...). This is the dark purple diamond weave (3-fold construction) in action.