I fear i am going to be in the minority here if it's put to a vote but i can happily report that a Monaco on a well made black or dark blue rally strap is my preference. Its a tactile balance between the hard, sharpe edges of the steel case and the soft "earthy" feel for a good quality strap.
Pictured below is a favourite combination - a nice Monaco (sadly moved on to a new home) on the dark blue leather rally strap that Squinky has/had in stock. It was a great look & feel.

Worth mentioning - i enjoy my Chronomatic paintless wonder on a black corfam strap.

Cheers - Darren