[Ewierl]

Personally, I always like Vine Ogres. Not fantastic in any way, but their beauty is cost-efficacy: 2 gems per casting, and each casting can easily become 100hp of meatshield (and much more in the mid/late game as you have Ivy Kings and the like). They're slow to mass, but completely upkeep-free, so you can accumulate a lot of cheap goons, especially if have many mid-level N mages.