Summons: Your thoughts.....

[K]

So, in Dom II I used to summon things quite a bit. Armies sucked and were hard to build, so your army eventually became composed entirely of summons.

In dom III, with the exception of a few notably great summons, I generally make armies out of recruitable units and save the gems for battlefield spells, rituals, and items, or I spend them on summonable commanders.

So my question is this: are there any summons you use as a part of your strategy? Any great stories from MP or SP about a lesser used summons that paid off? How do you use your summons: support troops, frontline troops, or chaff, or some other roll?