I'm of the firm "no magic zombies" camp.
If the zombies aren't magic, they aren't going to last long, whichever form of zombie they are. Wait inside a few days, most of them should be dead or immobile.
If a zombie loses blood, they aren't going to keep walking, their muscles won't work without blood.
If you have a strong door, zombie arms will break before the door breaks.
Dehydration. Organisms need water to function at all, let alone move, and zombies aren't big on water fountains.
I see zombies as dangerous for a few days, with their senses failing so they can't track you effectively for the majority of the outbreak, then it's over.
Anything other than that scenario is a magical zombie, who can move without energy, function without a body, or unrealistically mutate.
I love zombie movies and comics, but for real real, no magic zombies.
update: I'm going to do a podcast episode about magical zombies now.