Have you decided on a brand and model? Its good to research on this before you go to sim lim. You will be better prepared and not get 'convinced' easily into buying a mic you dont need. The sales ppl there are knowledgeable, but in the end, they cant decide for you - you have to know what to buy.
I am using rode ntg-2 for my dvx. Not the best, but good enough for my budget.