I think I'd go for Goa'uld...
The wraith are extremely numerous but in reasonable numbers were destroyed by the Ancients. In sufficiently small numbers even ballistically armed humans can kill them, eventually. However, basically all they do is hunt for food: little more than subsistence farming.
The Goa'uld are political, scavenging, enslaving and will make opportunity to grab people, property and planets whenever they can. We have seen massive, layered plans within plans, strategies, alliances and feuds. (But we've only seen one series of wraith.)
If you want scary, how about a Goa'uld in a wraith host....:evil: