It should affect any attacks made by you, spells, melee, whatever. As far as gear, here are some ideas (assuming all gear is perfect):

Helm: Crown of Ages (2x 5/5 Lit Facet)
Armor: 'Chains of Honor' High Def Armor
Weapon: 'Heart of the Oak' Flail
Weapon Switch: 'Call to Arms' Weapon and Lidless Wall
Shield: Herald of Zakarum (5/5 Lit Facet)
Gloves: Frostburn
Belt: Verdungo's
Boots: Aldur's Advance or Good Rare with High Resists
Ring1:Stone of Jordan
Ring2:Raven Frost
Amulet: Mara's or Armageddon Slippers

Charms: 10x Pally combat with any following 2nd mods:
+life/FHR/Faster Run-Walk.
Annihilus
9x Vita/Shimmering/R/W charms.

Base Stats:
STR: 109
DEX: Enough for 75% block with maxed Holy Shield
VIT: All available points here
ENE: Base

Ok, this gives you a stunning +235 All Resists (assuming no +resists on charms except Annihilus). That will help combat any Lower Resist effects. You can also have some absorb gear in stash for emergencies.

Skills to max: Fist of the Heavens, Holy Shock, Holy Shield.

Place 13 points into Conviction.

Fill prereqs and put 1 point into Salvation.

Any left over points should likely go into Defiance, to help boost your Def.

Basic perks:
A level 44 FoH, level 32 Conviction (total -165 to enemies' lit resist), and over maxed resists in Hell.

This was built without any 'Ladder Only' gear.

No animals were harmed in the making of this post.