Gifts for BM's?

I was oringially going to get my BM's the DOJ, but yesterday I was in the mall with my MOH, and we saw jewelry we liked. I ordered it, and left the deposit. Then my MOH asked if I was planning on buying it, or if I wanted them to buy their own DOJ. If I buy it, what do I do for the rehearsal dinner? Woud I still give them something else? If they buy it, what else can I get them that might be more personal? I like the idea of them buying the DOJ and getting them a more 'personal' gift...but what?