Replacement of hard drive in WD mybook enclosure

well I broke my 500gb WD mybook I broke something inside the hard drive .
when i turn it on, it spins off-the center and the weight of the hd was shifting in my hand . when i power it up and connect to my pc it not showing me any applications in it and some error comes up and says I/O error . then i took the enclosure apart from the hard drive and try to find that it would be very easy to replace the drive instead of buying another drive with an enclosure

Its a standard sata drive, i could buy a replacement for about 40 bucks less by buying the drive..and this time i need more space in it :).
i find this from newegg Samsung 750gb drive with a 32mb cache for 130 bucks i thinking of replacing it . if i dont go with the Brand then im thinking of WD drive that's 750mb cache and only 16mb cache for 105 bucks what to do guys should i get a new one ?
need advice

i did some research and find that my book is called a Green power driveand it is used 33% less power than normal drives
i did some research on the Samsung 750gb drive with a 32mb cache and the official samsung site says that it has spinup current of 2.4 amp
and what is your out put of power supply ?
if it is low then the sam sung one then my suggestion would be go with a another low power drive

my power supply 2.1 amp it is lower....but i dont want to spend more then 95 $ or 130$ !

i think that if the it is a lower power drive and has SATA is connected to it, for the time its worth it

Ok, so i finally bought a drive. Its came out of it: WD5000AAAKS 500gb drive. It is working fine ,