Well I don't know what all towers are, I don't think anybody does for sure, but I'll try to list them best as I can.
Walk-Brass: Disabled (Dragon broke, during Daggerfell)
Red-Mountain: Disabled (Disabled during events of Morrowind)
White-Gold: Disabled (Destroyed by the Oblivion crisis)
Crystal like Law: Disabled (Destroyed during the Oblivion crisis)
Snow-Throat: Disabled (No real idea why, there are some theories floating around the forum though)
Adamantine: Enabled, the Ur tower, zero stone whatever. The first tower ever made.
Those are all pretty much confirmed towers, some would assume the Hist is a tower as well, others say that Khajiit are either a tower or a stone. It all becomes a bunch of speculation however and far as I know no conclusive evidence has been given pointing one way or the other.
As for speculative towers:
Falinesti, the walking city in Valenwood. No idea what the status is, but I'm guessing disabled.
Orichalc??? No idea about this one to be honest.
Wait, let's be clear here:
White-gold may still be active. There are multiple theories supporting the fact that there is a new stone, although my money is on it disabled.
Snow-throat is more than likely still active, unless you have some evidence I haven't come across. We don't even know what the stone is.
Brass might still be active aswell, unless again you have information I don't.
Falinesti may still be active aswell. Shouldn't just guess about these things, it's confusing enough as it is.
Orchalc, Red mountain, and Crystal-like-law are afaik the only ones you can say without doubt are destroyed.