panaflows are great and can be quiet(the quiet models are) but that Sanyo Denki is too. It is also a thicker fan meaning it will give better airflow at a more constant rate. But Panaflows are great too.
If you are only going to have 1 fan in inventory, I keep a good mixed stock but if I were limited to just 1 it would be the 80mm 47cfm Panflow. Reason? mounts in all cases without mods or in increased # with some hole cutting you can get very high airflow through the case. Also 80mm fans can be adapted easily to many HSF's that are out there.
I recomend you do what I do and keep about 6 of each of the following fans in stock for those late night progects when everyplace is closed.