@Slarti I think your reading are kinda good. Did you meter the voltage on those pots?... The ADC will show you 0 when voltage is 0V and 1024 with it register 5V. So, it's a problem at the connections (poor connection, cold joints, small section in the wires...) or pots might be conductive (dirty maybe).
I did check my joystick and found out that even-thou the usb rail is providing 5.16 V with it connects to the Arduino board it drops to 4.68... rough guess is that it's a protection diode voltage drop. I'll research later how to apply 5V directly. For example in my potentiometers the ADC reads from 0 to 960...
