It really depends on what you plan on doin. If your goin to the beach then you probably should bring a backpack (for beach things). I would bring the hawaii one since u r in hawaii. Only bring a purse if u just plan on just shoppin or walkin around , not really doing an excursion or anything.
I would suggest bringing the backpack. When you're going to the beach, you have to bring a lot with you (think: towels, sunscreen, etc.) Not all of that will fit in a purse or minibackpack. Plus, the backpack will stay on your back, so unlike a purse, it will be hard to lose.