My approach to boss fights would be defense first. If I can assure myself that I have best possible defense for my characters against a formidable boss, then my offensive power will follow more naturally than finding out during battle that I have sub par defense stats.
That being said, I believe the best armor for the men would most likely be:
OzziePants, Moon Armor, and Power Seal.
Or if you're playing the DS version, it would be:
Ozzie Pants, Saurian Leathers/Regal Plate/Shadowplume Robe (Magus only), and Power Seal.
I believe the best armor for the women (either version) would most likely be:
OzziePants, Prism Dress, and Power Seal.
No, sorry defense is not THAT important. Status protection is much more important for the final battles. Plus ozziepants have autoconfuse on them.
In the SNES/PS1 version, best gear is as follows:
Males: Haste Helm, Nova Armor, PrismSpecs
Females: PrismHelm, PrismDress, PrismSpecs
Weapons:
Crono - Rainbow; Marle - Valkyrie; Lucca - Wondershot; Ayla - Bronze Fist; Frog - Masamune; Robo - Crisis Arm; Magus - Doom Sickle
In the DS Version:
Males: Master's Crown; Regal Armor, Prism Specs
(All Males except secret character and Robo's alternate setup)
Females except Lucca: Angel's Tiara, Regal Gown, PrismSpecs
Lucca replace the Regal Gown with Elemental Aegis
Weapons: Crono - Dreamseeker; Marle - Venus Bow; Lucca - Spellslinger; Ayla - Bronze Fist; Frog - Masamune
; Robo - Crisis or Apoc Arm*; Magus - Dreamreaper
Robo's Alternate Best Setup: Apoc Arm, Haste Helm, Nova Armor, Dragon's Tear (This setup is broken and way too abusable)
This damage does 9999 on critical but crap other wise, so imo it would be best to have autohaste on him so he can attack as frequently as possible, and dragon's tear to up the critical rate
On my first playthrough, no NG+ here's how all of my characters are set up:
I only have 2 prism specs, 1 dragon's tear, 2 master crowns, 1 regal gown, and 1 angel's tiara so I gear swap a lot depending on who I have in my party. I have 3 Prism Dresses and 6 Prism Helms though from doing the Black omen in the present, then 600 ad, then finally antiquity and charming them off of zeal. That nets 3 helms and 3 dresses, and for the rainbow shell reward, I chose to get 3 prism helms.
Crono - Dreamseeker, Master's Crown, Regal Armor, PrismSpecs (Magic is at 70ish, so I think I can do about 3k of damage with Luminaire to the new boss, 6k on normal monsters)
Marle - Venus Bow, Prism Helm, PrismDress, GoldStud (I don't really use her that much...)
Lucca - Spellslinger, Prism Helm/Angel's Tiara, Elemental Aegis, GoldStud/PrismSpecs
Ayla - Iron Fist, Angel's Tiara/Prism Helm, Regal Gown, Valor Crest/Prism Specs
Frog - Masamune, PrismHelm, Saurian Armor, Champion's Badge
Robo - Apoc Arm, Haste Helm, Nova Armor, Dragon's Tear
Magus - Dreamreaper, Master's Crown, Shadowplume Robe, Gold Stud/Dragon's Tear/PrismSpecs
Imo, PrismSpecs payoff more then dragon's tear on Magus, cause then you have higher damage overall overtime, and criticals hurt a hell of a lot more.
Robo is just broken with that setup. I don't use Regal Armor + Master Crown on him because doubling his crap damage still makes him do crap damage. His critical is the only thing you want from him with the apoc arm, so you absolutely NEED dragon's tear to make it worthwhile. Otherwise just use PrismSpecs + Crisis arm with the Mastercrown and regal armor. I try not to use robo too much though, cause he just makes the game too easy. He has the best single tech heal in the game (Heal Beam), can dish out the most damage with either the apoc arm OR crisis arm setup, and has both a good physical tech and spell.
The team I like to use for most battles is : Crono, Ayla, Magus. It's not even that great of a team since it doesn't have a good healer, but I like Magus a lot
The absolute best team in the game is: Crono, Ayla, Robo. If you lose with this team to ANY boss, you suck. If you have robo's apoc arm setup, you can probably beat the dream devourer without even healing once.
Worst team at deal damage is probably Frog, Magus, Marle. At least if you use Lucca, you can team up with Marle for Antipode Bomb III. This team has got nuthin, LOL
Although Magus is my favorite character, sadly he becomes much less useful overtime. No dual techs and dark matter is the weakest ultimate in the game. I wish Square would've given it a multiplier that could compete with Luminaire, cause then Magus would a lot more amazing. Hell, I'd even venture to say they they should've given dark matter a multiplier of 22, since magus is *Supposed* to be the strongest magician in the game. But my rantings about Magus' shortcomings won't change a thing.