Dizzies, because they're like plasma cannons but give you more offense power for same credit consumption. They're also much better against interceptors than fighters or bcs, and give you more offense per resource value, so if you're using infests they're the best way to build up an army.
RawPotato said:
Cyborgs, because they are free and they are both off and def so they are good for capturing and protecting depos
I found a guy once who had 2.5k cyborgs on a deposit (now that's a lot of alts haha). When I smashed it with dizzys and took zero losses he got rather angry :P