Most Usefull Research Path...

[PsiSoldier]

It also depends on what size map you are playing, If you are playing on a very large map then Alteration is Hands down the best choice. Just create a pretender with huge astral skill, Do everything you can to find Astral sites and start Wishing for whatever unit or artifact you want and wish for strength and more magic power.

Of course thats not to mention all the Good buff spells like Body Etheral, Luck, Mistform, Invulnerability, Pheonix pyre etc. to keep your mage\SC alive on top of the Chalice and other Artifacts you have already wished away from the dude with the Construction tree.

Plus you get a few descent globals like Fata Morgana and Mother oak, though you couldnt use Utterdark to your advantage unless you were playing LA Ermor in which case you would own even more.