Haven buildings.

I disagree; in my opinion, it's the most advantageous option in most cases: mage - djinn - dragon golem.

In most cases?))...
With Necromancers, mages aren't needed (if you're using undead), and you don't want to take risks (guessing what the enemy is building)...
There's also little point against Chaos, as they have flying units, a decent ranged attacker, and area-of-effect magic... and golems have resistance to it.
It's also dangerous against Barbarians, as Cyclops can take out everyone at once. And if you spread out the archers, the infantry might reach them... in that case, you won't even have time to cover everyone. Plus, they have high magic resistance.
It's easier against Life and Nature, although the latter can cause trouble with dragons and other flying units.

But a golem-dragon is good against Necromancers, as magic doesn't affect them. And it's debatable against Chaos, as the Titan has protection against Chaos =)
Against Life and Nature, the Titan is better, as Life usually develops into infantry, and it's good to shoot them down. And Nature, on the other hand, develops into archers, so a fight might not even happen (with the Sand Striders) =)))

P.S. Although, who knows... a lot depends on chance, the map, the opponent, and their development =)