Bar 1 - Destro Flame Staff: This bar is for single target sustained damage with burst potential if you time it right.
Crystal Frags: High Damage with a 2 second stun and a chance at insta cast/reduced cost/MORE damage
Haunting Curse: curse that deals damage twice, but it takes longer. This will be, ideally, low maintenance sustained damage.
Crushing Shock: Staple Destro skill, and puts enemy casters off balance after interrupting them.
Destructive Clench: Some CC, Damage, and a DoT. Can potentially be replaced with something else but this seems to be a good choice.
elemental Drain: Major Breach on the enemiy, plus Minor Magickasteal for sustain.
Ultimate - Shooting Star: Primary reason for this choice was to keep 1 Mages guild ability on each bar for the passives, but it's a great ult

Bar 2 - Resto Staff: Shields and Mobility, as well as some basic life gain.
Hardened War: Damage Shields
Healing Ward: Healing and Damage Shields
Streak: CC and mobility rolled into one.
Degeneration: Damage and also healing, AND lifesteal. PLUS Major Sorcery, and the Mage's guild passive. This is borderline more a buff than anything else.
Daedric Minefield: Breathing room and Defensive Damage, Makes it harder for Melee to stick to you.
Ultimate - Temporal Guard: Flat Damage reduction, plus an Oh Shit button. Could be replaced with The Dark Magic or Resto Staff Ultimates.