Ideally, the more sword you are exposed to the easier it is to decide on what you want. Otherwise you have to go with your period of historical interest and your own personal style of movement. You may want a rapier only to discover later that you don't really care for its demanding style of thrusting fence. Thus, the more information you have about what a particular sword design was used for and when and where, the easier it is to know what you want. Let's be honest.
Swords are cool.
There is all at once something romantic, adventurous, historical, exciting, menacing, intimidating, heroic, and something gallant about them. Even without training with one or knowing its use, simply owning one, possessing it, holding it, looking at it, showing it off, caring for it, and pondering on it, is all part of its mystique and culture. But exactly what you want your sword for is a consideration that is should not be neglected. You get what fits your interests, your pocket book, and your needs. If so, you'll want the most accurate, light, and sturdy blade possible.