Hair color help.

jane
Hey so I leave next Wednesday for Ireland, and I'm getting my hair colored but I don't know what color would look good. 
I've tried a bunch of colors ( blue, stop sign red, burgundy, blonde, black to name a few) so I'm not afraid of to try different colors. 
I'm pretty sure, my boyfriend will propose while in Ireland too so I want to make sure if we do get engaged my hair looks good for pictures. 
Oh and my hair is naturally brown.