I normally use a D-lock plus cable for the other wheel when about town. That's on the low end of London standards, and vastly exceeds the standard of locking that's usual here in Birmingham (Poundland combination cable locks are gradually being replaced by D-locks around the toptube, thanks to an anti-bike-theft campaign by the university). While I do have security QRs on my most-used bikes, I consider them redundant when there's a lock through the wheel.
If I'm using cafe or touring quality locking (basic cable or Bordo Lite[1]) in a low-risk situation, I consider anything that requires a tool to be sufficient for securing the wheels. Standard wheel nuts would qualify.
[1] Marginally better than a cable lock, but has the psychological advantage of looking like a Bordo, for a fraction of the weight.