I just bought a 1TB external HD, the "Maxtor OneTouch 4 Plus" this weekend on sale at London Drugs. A bit of an impulse purchase but I've been digiizing all of our dvd's lately into iTunes and had completely run out of space...
The drive has a bunch of automated backup features I'll never use, so I skipped all the software and went to use the drive directly from Mac OS X. First step here is to convert the format of the drive from it's default of NTFS to something Mac can natively use. My impulse was to simply "format" and continue but unfortunately every time I tried the format disk utility would abort with nothing useful showing in the console logs. I went through this a few times with different file system settings and nothing worked. (See this ArsTechnica link for how to choose your filesystem)
I then tried to partition the drive - and two partitions or more would all of a sudden work. Again odd, but I didn't want more than one partition in this case, but reverting back to one partition would cause the same problem all over again. I resorted to Google at this point and came across this very useful although somewhat poorly formatted post on Seagate forums. (seems to be a generic problem with disk utility)
The gist of the problem being that the default partition table format needs to be changed to GUID. You can apparently only acheive this by partitioning (in this case to two partitions) so you can change the setting for partition table format and then partitioning again back to one partition with the new partition table format intact. Annoying but easily worked around once you stumble on the right answer.
Note this issue is actually new to 10.5.* and you can also solve the problem by formatting from an older version of Mac OS X (from a boot CD for example).