Frankly, whoever is willing to pay foots the bill for the wedding. Today's couples are typically marrying later in life than they were in previous generations, and brides and grooms have often left home, developed their careers and in some cases have already established a household with their betrothed. These couples are generally covering more, if not all, of their wedding costs, although often with a significant contribution from the bride's parents, or both sets of parents.
If a bride's parents wish to host the wedding or contribute substantially to the cost, and the bride and groom have no objection, the bride's parents should be afforded their traditional role as hosts of the wedding. If the groom's parents offer to host or make a significant contribution to the costs, and their offer is accepted, they should be given the appropriate honors associated with the role of host. No bride and groom has a right to expect or demand that their parents pay for or contribute to the cost of the wedding; nor is it appropriate to expect anyone to contribute any more than they offer to or are able. One set of parents should not feel obligated or challenged to contribute as much as the other set of parents, especially if it is beyond their means.
A gracious bride and groom will recognize that their parent's financial contribution to their wedding is a gift, and they should accept the gift with the appropriate gratitude. While you can certainly work with your parents to create a wedding that you all like, it is not appropriate to assume that you (the bride and groom) have the final say in how someone else's money is spent. If your parents are contributing to the cost of your wedding, it is reasonable for them to expect to have some influence over the decisions made. If you don't like the decisions your parents are making and a compromise can not be reached, you may have to consider paying for your wedding yourself so you can do it all exactly the way you want.