They do have enhanced senses. Their hearing is sensitive enough to clearly hear and follow every sound and conversation within a twenty mile radius of their location. Their sight, under perfect conditions, can see the smallest molecules of any object up to five-hundred miles away. The reason for this extreme ability is because of being nocturnal. In order to be of any use to them, their eyes must be able to capture and clearly see even the smallest fragment of light, no matter the distance from them. Otherwise, their sight would be almost useless to them.
Their senses of smell, taste, and touch are a lot more close range and concentrated in comparison. For example, their sense of smell can capture scents up to twenty miles away, but it isn't until the source of that scent comes into about a five mile radius of them that they are actually able to tell distinct details about the source. Even so, the closer the source of the smell is, the more subtle details the vampire can pick up on through the source's scent alone. Taste wise, they are pure carnivores and therefore their sense of taste actually compliments their sense of smell once the source of a scent comes within a one mile radius of them. At that point, it is almost as if they can taste the scent within the air, thereby allowing them to instantly know just how edible the source of that scent really is. This is when they can tell exactly what a living or undead being really is, as their taste emphasizes their sense of smell just enough to tell tasty details otherwise impossible for them to know.
Finally, you have their sense of touch. Despite their skin being tougher than leather, their sense of touch is actually very sensitive. So sensitive, in fact, that they can feel someone's pulse pounding against their eardrums up to one-hundred yards away. With this in mind, you can understand why a vampire takes comfort measures when it comes to sunlight, despite it not being able to harm them. The only way it could ever harm them is if an undead vampire stays in direct sunlight too long without protection, like sunscreen for example. Why? Because like all of us, they are sensitive enough to get a nasty, bright red sunburn. All in all, they are truly made for the nocturnal environment.