I bought a maxtor ata133 drive. Its pretty good but drove me round the bend for awhile. It made a loud clicking sound when in use (not the horrible screeching, grinding sound when drives fail just the sounds of the drive heads parking).
If you get the same sound go to maxtor support and get them to email you thier amset utility. I got that and its as quiet as my old seagate.
Doh sorry just realised you got the ata100 one, dont know if they have this prob. sorry