Yeah, well, most of the low-level summons *are* lemons.
Except for some of the nationals. Right now, I like LA Agartha's Conj 4 Sepulchrals. Sacred, high-damage (24 Str + 11), decent attack, great protection (E9 + Legions of Steel = 20 Prot), cheap (4 death gems). Zero-encumbrance, and we all know how important that is. 65 hp and size 4 means even anti-undead spells like Dust to Dust don't have an easy time taking them down.
Flame Corpses (also LA Agartha) look promising, but I tried them against EA Pangaea's centaurs and they didn't kill many, probably because they centaurs have so many hit points. I think I'd rather spend the fire gems on Lightless Lanterns, but if anyone knows a good use for Flame Corpses I'll be glad to hear it.
-Max