Warlock equipment

Armor
Warlocks are proficient with Light Armor and they can cast spells in Light Armor without having to worry about Arcane Spell Failure. Warlocks who invest in Enlightened Spirit enhancements can eventually pick up Medium Armor proficiency (and the ability to ignore ASF in medium armor).

Weapons and shields
Warlocks are proficients with simple weapons and no shields. Fortunately, Warlocks have access to Master's Touch spell to gain proficiency. Warlocks can also gain proficiency with all martial weapons by investing in Enlightened Spirit enhancements.

Eldritch Blast and many spell-like abilities that Warlocks can access via enhancements are not subject to ASF at all. Some warlocks who value defense over spell-casting can wear Heavy Armor and Tower Shield without proficiency.

Spellcasting equipment
An overview of Spell Power that increases Warlocks' Eldritch Blast is available here.

Most Warlock spells don't deal hit point damage. A notable exception is Evard's Black Tentacles, which deals bludgeoning damage (increased by Impulse / Kinetic lore).

Depending on their focus, some Warlocks increase the DC to resist their spells and spell penetration:
 * Evocation increases the DC to save versus Eldritch Blast pact damage.
 * Enchantment fuels many crowd control spells and SLAs from the Tainted Scholar enhancements and various pact spells
 * Necromancy helps Warlocks to land their insta-kill spells and SLAs from Soul Eater enhancements
 * Conjuration: Evard's Black Tentacles