I'm making a Soulfire Master/Devourer Thaumaturge and I'm being given the option of gestalting with a few restrictions:
If I gain another casting progression, I only gain the better of the two, not both. This progression can benefit from spell-modifying class abilities of both classes where appropriate.
Spherecasting is the only available type of spellcasting, although spell-likes work as normal.
The character is a creepy destruction/dark cultist weirdo that wants to wield the hideous powers of the enemy (not that we know exactly what the enemy is yet) against its own forces.
At the moment I'm thinking of taking Incanter as my other half, gaining an eventual +20 talents over what Thaumaturge would normally have. It does, however, leave two bad saves. :I
Incanter as you mentioned is an obvious choice to get more talents. Devourer would gestalt nicely with magus; two levels get you spell combat, more get you extra SP or you move to something else.
Elementalist could get you all good saves and a damage boost, plus dodge bonus, feats, flight, etc.
Guess it depends on desired versatility. If you want to be up front breaking stuff with critical hits and destruction, magus 2/elementalist.
Might seem an odd choice, but get adept at 6 becomes awesomely versatile, especially with your ability to boost save DCs.
The best 'power' answer is hedgewitch with spiritualism of course (maybe combat for the second one to get weapon and armor proficiency and such). I wouldn't though, as it is extremely powerful in gestalt.
Fey adept. Stupid phone. Create reality is amazing for pretending you have a bunch of spheres.
And whenever i see devourer my mind goes straight to a magus dip to get more crits.
Turning a familiar into a receptacle for burn at level 7 is very nice also, so consider getting one via class, feat, or whatever. Just make sure it's not immune to CON damage (undead or construct pretty much).
I'm being allowed to use a custom archetype for Elementalist that's focused on darkness as an 'element'. No nature stuff, though.
Here's the stuff:
++ Shadow Weaver
+++ Shadow Focus (Su)
At 3rd level, a shadow weaver adds 1/2 their elementalist level to all damage dealt with negative energy blasts.
At 9th level, This bonus damage increases to become equal to their elementalist level, and the elementalist may use their class level as their caster level when using the Dark sphere. This stacks normally with caster levels gained from other sources.
At 15th level, the bonus damage increases to 1.5 times their elementalist level, and they gain a +2 bonus to their caster level with the Dark sphere.
This replaces Favored Element.
+++ Shadow Defense (Ex)
At 5th level, a shadow weaver gains a +2 bonus on saving throws against negative energy, death effects, effects from the Dark sphere and spells with the shadow descriptor. This bonus increases by an additional +1 every 5 levels thereafter. At 20th level, the shadow weaver becomes immune to those effects.
This replaces Elemental Defense.
+++ Shadow Movement (Su)
At 7th level, a shadow weaver gains the ability to use a move action to teleport up to 20 ft. between two spaces of dim or lower illumination. This improves to 40 ft. at 13th and 60 ft. 19th levels.
This replaces Elemental Movement.
+++ Shadow Body
At 20th level, the shadow weaver’s body has become infused with the power of darkness. They gain immunity to sneak attacks and critical hits, and gain DR 10/magic.
This replaces Energy Body.
Yeah, it's a good idea to have at least two elements for your destructive blasts. XD The Gloom, Nether, and Tenebrous blasts just apply penalties (admittedly some fairly decent ones if you have teammates that can follow through). Stone Blast is a pretty decent choice if you want to go that route. Or you could just grab some undead-controling powers, I suppose...