Interesting read re towing hook locations, having had to tow my car twice now with no tow hook I've used the front crossmember/subframe however now getting to the point that I'm thinking it may be a sensible addition.
Thinking of keeping it subtle I've got one from the stock tie down location however as now mentioned it'll likely interact with the valence. May have to reconsider to somthing more like that suggested by Mike, albeit black to blend in a little more. Hmmm... either that or a tow strap tucked away in a similar location.