I thought I'd try to compile a nice list of equips that are good for Shot (Destruction) Mages since people are often asking what equips are good for so and so class. Unfortunately I don't know anything about other classes so I'll stick to my own.
So here goes. Obviously very important is damage bonuses. While +magic bonuses are good for lower levels +% bonuses are way better once you higher levels (and not even that high). Also +magic bonuses on a lot of equips is misleading. Often these bonuses don't mean that you get a higher magic stat, but just that you get extra magic defense. The only equips that raise your magic stat are rings, earrings, and extensions. All other body parts mean magical defense when they have a +magic stat. Of course when the equip says +% damage your damage increases.
Second most important (in my opinion) is skill cool down times. This is very important for mages who plan on maxing the Destruction Magic expertise and want to use those -dyne and almighty skills to the fullest. These skills, while awesomely powerful, have very long cooldown times, so you will mostly be using mid-damage skills with an occasional -dyne skill thrown in. However, if you manage to lower the cooldown time you can use the high damage skills all the time and not stand around waiting for the skill to be usable again.
I'll update it when I find more stuff, and please feel free to make suggestions.
Yes, I know, I talk too much. So here's the list:
Weapons
Epee (+44 spell damage)
Poseidon's Trident (+37 spell, +20% ice-based skill effect)
Phlogiston (+35 spell, +3 consecutive agi and agilao attacks allowed)
Eistanzer (+3 consecutive bufu and bufula attacks allowed)
Sets
Supremacy Sets (reduces incantation and cooldown times)
Red Rider's Sets: Red, White, Blue (gives +% elemental damage)
Purple Rider's Set (gives +% damage)
Summer Gothic Sets (-40% incantation and cooldown if you have the full set)
Tops
Fighting Maid's Dress (-25% incantation and cooldown)
Outlaw Cloak (+8% damage, and +6% damage to all party members)
Salon Dress (+6% fire and ice damage)
Jasmine (+12% damage, +6% fire, ice, magic skill effect if demon is Open Hearts or above)
Mint (+8% fire, ice, magic skill effect, +12% damage if demon is Open Hearts or above)
Bottoms
Santa Pants or Santa Miniskirt (+6% damage, -10% incantation and cooldown)
Ambitious Slacks (+10 magic, +7% damage)
Noh Pants (Drifting Boat) (m) (+4% spell damage)
Mysterious Slacks (f) (-15% cool down time)
Accessories
Iced Earring: Praying Flash (law, +spell damage)
Seeking Earring: Praying Flash (neutral, +spell damage)
Fury Earring: Praying Flash (chaos, +spell damage)
Shamrock Necklace (+5% damage, +20% expel)
Mithra's Guidance (+12% spell damage if demon is Open Hearts or above)
Emerald Flare (+8% spell damage)
Christmas Sapphire Ring (+8% spell damage)
Face
Cheating Glasses (+5% damage)
Outlaw Glasses (+5% damage, +4% damage to all party members)
Head
Replica Helm (+3% damage)
Comps
Amplifier Comp (+10% damage)
Magic Amplifier (+12% spell damage)
Silver Pallidion (+15% damage)
Tarots and Soul Stones
Tarots:
III of Rods (mgc +3)
IV of Rods (mgc +4)
Elf (Mgc +2, Spd -1, str -1)
Decarabia (Mgc +2)
Soul stones:
Kikuri Hime (ring, earring, talisman, extra) (mgc +1, int +1)