Most Usefull Research Path...

[Humakty]

I don't trust SC (had some bad (but short) experiences with them), so I would say enchantment, for all the reasons developped above by more experienced players.

I will had the summons are easy to cast, as a 1D mage can search for sites pretty easily, so you don't need much effort before starting to trample the ennemy's elites.(If you understand what spell I'm pointing)

PS : I preffer to field ubber battle mages, rather than SC, I find them to kill more ennemies for the same cost in gems.

[Baalz]

One other consideration - in theory you can trade for construction items. I know that if I can line up a good trading partner early I'm much more likely to ignore construction for a bit. And some of the con-0 stuff you can do without research is decent, particularly the earth items, I think you could have a pretty decent thug without any construction research - if you had the right chasis.