MarkT:
There's no such thing as a single-supply opamp, all opamps have a single supply!
Ehh... while I see your point, I take exception with the wording. I'm sure this is obvious to most, but it's extremely common to use the phrase "single supply" to refer to Gnd/Vcc supplies, and "dual supply" to refer to V+/V- supplies, where Gnd is presumably in the exact middle to support symmetric AC signals.
They both use a single pair of supply pins, sure, but one is made from a single PSU rail, the other from dual rails, hence the difference in terminology. You'll confuse the heck out of a new guy for insisting differently. 
IMHO, of course.