before I confuse myself anymore....
Summary:
According to mattallen... the 5v regulator can supply up to 800mA.
The servo motors I'm using can draw.... erm... they actually state 2 different sets of values for some reason:
120mA at no load and 800mA at stall, and the second set of value states 110mA at no load and 415mA at stall. So not really sure which one to go with :-s
I don't think this applies to the data wire but if it does it would indeed be overloading the data pins on the arduino as mattallen stated earlier... I doubt this though as they would have burnt out long ago since I've been using it as it is for quite a while.
So... I guess for now the easiest thing to try would be to power the motors from a separate supply e.g. a 9v battery.