For themes there are a few that I think have the necissary "recognition" to get everyone excited.
Necromancer
Bad Moon Rising - Creedence Clearwater Revival (This one could also go with the Arraxian Crown Warlock).
Warlock (Arraxian Crown)
I Put a Spell on You - Screamin' Jay Hawkins (I noticed you have this for the Wizard, but it makes me immediately think of the Warlock and his curses).
Warlock (Adramelech)
Black Magic Woman - Carlos Santana
Warlock (Either)
Superstion - Stevie Wonder
Warlord (Anvil Throne)
In the Hall of the Mountain King - Edvard Grieg
I'm going to keep thinkn' about this today, and see what we can come up with.