I agree, it sounds like you just haven't burped it fully. Has the car ever shown any signs of being overheated on the gauge?
When I do anything that requires changing coolant I run the car with a funnel in the upper res. and keep it running until the car gets up to temp and the fans cycle twice on their own, while the heat in the car is set on full, but keep the blower fan off. This can take quite awhile with a big rad, I would say it takes me around an hour generally, and I have a big 3 core aluminum rad.
The sensor that controls the fans is on the water pipe under the intake manifold, behind the alternator, just as an fyi.