[Zigûr]

Originally Posted by Inziladun

Alternately, maybe he himself didn't make use of weapons, thinking he could accomplish his victories with his aura of terror, or that failing, with brute strength.

I personally take this view. I've never imagined Sauron coming out in armour and wielding a weapon, I actually always imagined him unarmed and unarmoured, trying to overwhelm Gil-galad and Elendil through furious raw strength and the sheer awfulness of his presence.

Originally Posted by William Cloud Hicklin

Note also this, from the Scroll of Isildur:

...Sauron's hand, which was black and yet burned like fire, and so Gil-galad was destroyed

This occurred to me too. Sauron could apparently burn with a touch, so perhaps he would not need conventional weapons.
"But at last the siege was so strait that Sauron himself came forth"
This was an act of desperation, not a calculated military manoeuvre. Sauron never expected to have to actually fight his enemies.

Originally Posted by Dark Lord

Sauron fought in battles didn't he?

Almost never. The films portray Sauron weighing into the battle on the slopes of Orodruin as some kind of doomsday for the Last Alliance, but really it was Sauron's final gambit and one which didn't really work.

But, when you ask someone 'What was Sauron's weapon and what did it do?', most people would reply with the description of what showed in the movie, not say 'It wasn't stated'. - That's if they know much about LOTR.

Would they? Surely someone who knew "much about LOTR" would know that it's never stated, although "most people" probably don't know "much about LOTR." Unless you mean "know the films well" or "treat the books and the films as interchangeable", which they're not, and which these days is a source of endless confusion. Anyway, just because a lot of people believe something doesn't mean that it's true. Just because the films have coloured people's imaginations doesn't mean that their depictions have the slightest relevance when it comes to discussing what Professor Tolkien himself actually wrote.

While some of the arguments here for why he could have had a mace are quite interesting, at the same time it's all just speculation because Professor Tolkien never wrote what weapon he used, if he even used one at all.