A (too) striking or attractive strap will distract from the worn watch 馃榾
On that basis a devilishly handsome fella like myself shouldn鈥檛 wear a nice watch because my gorgeousness would make the watch seem insignificant in comparison!
I personally like dark green or burgundy with gold, but it鈥檚 not just a matter of color, it鈥檚 also about texture and finish.
I would avoid straps that have a loud presence, such as straps with contrast stitching or heavily padded strap.
A gold watch is quite striking so it calls for a strap that鈥檚 streamlined and unobtrusive to complement the watch (elegantly in my opinion).
best example for me are the grained dark green @Pastorbottle posted, the burgundy strap paired with @Dan S鈥檚 IWC (even though it does have a bit of contrast on the stitch),
And all of the straps @YYTIN posted.