Are you refering to a capstone project for your undergraduate degree? Like the capstone projects for DNP degree? If so, then it doesn't really matter what you pick, but you could reference it when applying to graduate school on your CV. Getting into a MSN/DNP is mainly on grades and references. The GRE/MAT is looked at, but not extemely big determinants, when compared to other academic programs that place a hugh emphasis on them. Right now most DNP programs are geared to post MSN, so you would have to focus on that first. Until they start DNP programs as entry for advance practice in 2015. If your a junior now, then by the time you finish and get some clinical experience, you might be able to jump right into a DNP NP program. You would probably be one of the first graduates of the program. They should start opening in a few years to be ready for the deadline.
Also, for more information just do a websearch for graduate nursing schools. All the information you need on admission requirements are posted there. Could help you choose what organizations to join or activities to do to help you out on the application.