I use a maxtor one touch 4 750 GB (usb2) with my linux machine (ubuntu 7.10). I have formatted the disk with ext3 and it works fine.
Exiting from sleep mode the system often doesn't recognize correctly the disk (I leave the disk mounted): - some times i found the disk read-only - some times I cannot see correctly the files and folders - a few times it works
An answer would be appreciated, as I have a similar problem: no recognition at all of the HD under Ubuntu 8.04. HD works fine under XP and Vista though.
Please, Seagate/Maxtor, do not under estimate your Linux client base.