One thing that would make zombies scarier, in my opinion, is if an infected victim didn't die rapidly then turn, or simply turn rapidly like in 28 Days Later, but the transition to zombiehood was long, slow and terrible to see.
After the infectious bite, the victim first has a fever and flu-like symptoms as the virus makes itself at home, then the symptoms become unnoticeable for a while. Before the later course is known, the victim thinks they made it through. But slowly, an Alzeimher-like degenerative disease is taking place. The zombie instincts may appear early in, but are easily repressed by an active, conscious mind, and it would take a head trauma to bring them out. After a few months however, the victim begins to forget things, has trouble focusing, and often feels depressed or angry for no clear reason. The victim often daydreams about catching and eating other people, because while they are still sane enough not to do it, their brain's inhibition functions aren't good enough to keep it out of their conscious thoughts anymore. Gradually, they lose their skills, memories, and personality, down to the most primal emotions, who will fade in their turn, although at that point there already isn't enough of a mind left to keep from doing it. During that still feeling phase, the victim will call out to victims expecting them to come to them, smile gratefully at them for the happiness they gave them from being eaten, or crying when one escapes. And in the end, those emotions begin to happen in a less logical way, until the degenerating brain can't process them at all and ignores the feeble remaining signals.
Possibly, the victim is still able to eat normal food, if available, and drink from puddles. Since their brain consumes much less energy than normal, this gives them a rather long life expectancy. The virus may or may not also alter their physical functions to what we expect of a zombie. On one hand, an "undead" can be shot in the chest twenty times and still walk, but on the other hand, a breathing creature has much more energy to work with.
Do you have a similar concept in mind? How do you see it? If not, well how would you deal with what I described? Considering that a victim would still have several months of lucidity, and possibly become dangerous BEFORE losing their self awareness, at what point would you begin to think euthanasia is the best option? What if YOU were infected?