Just got my Champagne dress but what color should the guys wear?

I just purchased and loooove my champagne with lots of gold toned beads and love it but am not sure what color for the guys? The theme is very vintage and somewhat rustic, outfoors in the spring. Bridesmaids most likely plum purple (unless I find something else I like more) and the only thing I can think of is black with off white/cream/champagne shirts and whatever color tie I go with the girls dresses... But it seems toooooo formal for the theme! Maybe a charcoal? Also, had a hard time findin Tan that is affordable... I don't know, any suggestions?!?!