What are the best schools of magic to take spell focus in? Right now I want to pick up GSF Conj and GSF Evocation/Trans and can't decide which of the two to go with, or if I should go with them at all. Playing as an COTW Arcanist
Depends a lot for what. Conjuration allows you to pick augmented/superior summoning. Evocation increases the DC of Sirroco and other nasty spells. Necromancy from Finger of Death and Horrid Wilting
Just looking for all around good schools to take a second GSF in (or is it even worth taking another GSF? Can just boost the DC of any spell by 2 with potent magic exploit)
Conjuration, Evocation, and Enchantment probably give you the best mileage for your feats. In that order, to boot. Illusion is a good choice, but you'll have to wait for Level 4 spells for that to really pay off. Necromancy kicks in very late for arcane casters. Divination and Abjuration are nearly pointless to boost DC, and Universal is objectively useless to take a feat in. There are some people who really like Transmutation, but outside of Slow & Disintegrate, can't say I use that school much.
Conjuration >>> Evocation.
Illusion if you really insist to specialize in it. It actually has cool spells, including actual death effects, but there will be a significant group of enemies who will be immune.
Necromancy? For flavor maybe. Its really not that great. Some of the best Necro spells offer no save against suck anyway.
Enchantment? Please. Conjuration is soo much better its not even funny. AND there are no enemies immune to it. It even bypasses SR!
Only ever take Enchantment focus as a spellcasting-focused bard.
Transmutation? Nope. MAAYBE if you're a Disintegrate+Slow junkie, but really, its a waste.