Corruption because I like building my main base around an Altar and the Corruption ones look better.
Shadow Orbs look cooler floating around after removing the surrounding corruption
The Shadow Orb item is very useful to me prehardmode since I don't need to carry many torches
The Band of Star Power is far more useful than the Panic Necklace
Eater of Worlds drops one of those useless but cool pets
Scourge of the Corruptor fits my play style far better than Vampire Knives
I import crimson blocks from other worlds anyways so I can get most of the crimson specific items while keeping the Altars and Orbs that are specific to Corruption worlds.