What structure/unit do you build least?

Deepspace Orbital Radar. You only need one unless you're playing it safe.
Which is a shame, because they look absolutely awesome.

Most of the games I play see pretty much every structure and unit used. If you're only seeing T1 units and never see superweapons it means you're playing bad maps imo.

The units I see the least are probably scout ships, adv. combat fabbers and kestrels.

ADV combat fabbers can be a good first-through-gate unit because they can build AA turrets at scary fast rates.

I'm also surprised kestrels are so rarely used; I think they're awesome

I rarely build astraeus, skitters or gunboats.

Astraeus's are really terrible, just use orbital fabber and build a tele :3 Astraeus needs to be a multi unit orbital drop ship. Make it expensive but it should be fast and have reasonable health.

I rarely build defenses of all types...
no laser towers
no aa
no artillery
no catapults

only umbrella when really needed.