Crates are like square, and barrels are groovy, man. Barrels all the way. 

just slam into their crotch when they die and watch the physics-engine fun begin 

A barrel is essentially a round crate, so you're comparing apples to apples! 

But would that maze in Doom's E2M2 (or was it E2M3?) have been as tense if it had been barrels? 

its always crates. 

Crates can be stuffed with player items or even creatures for a sneaky ambush... barrels can be filled with water or explosive fluids... what's more fun, hacking open crates or igniting barrels? 

Crates can be stuffed with player items or even creatures for a sneaky ambush... barrels can be filled with water or explosive fluids... what's more fun, hacking open crates or igniting barrels?

Duke3D had two kinds of barrels: tattered barrels had items, and sludge-filled barrels exploded.

Also, some of the Quake 2 crates both exploded and had items in them. I never understood how the crate would explode but leave the rocket ammo untouched. 

I never understood how the crate would explode but leave the rocket ammo untouched.

Suspend your disbelief ;) 

crates > 1000*barrels.

crates are essential.

barrels are merely optional.

end of discussion. =)