Those are all really hot. I don't like to see mine past 40C (104F).
Since it's a Dell, I'd just keep my important data on another computer. If the drives fail, it's their fault and it should be covered by the warranty, right?
For comparison, my 74GB Raptor is running at 38C right now in a Sonata II with pretty poor airflow. Due to the rubber grommets, it's not even in contact with the case's steel, so it can't transfer its heat to the case. It's at least 75F in the room as well.
In my roomy Chieftec case, the Raptor ran at 32-33C most of the time.
My friend's Samsung 120GB SATA drive runs at 23-25C in his Sonata. I don't know how I pulled that off (I built it)...maybe the sensor is wrong.