A second hard disk is to be mounted. It will be a single partition , which will be used for file storage/ sharing .

Are there recommended conventions for doing this?

Q1: What should the filesystem type be? Journalised ext3?

Q2: What should the mount point be? I note that my HDD utility wants to mount the disk as /usr - but won't that conflict with /usr on HDA?

Thanks

The filesystem choice depends on how you want to share.
To share with windows OS it needs to be FAT32

To share with other linux users, networking any journalised will work. Most probably use either ext3 or reiserfs.

Mounting would be personal preference. The convention would be to create a directory under /mnt i.e. /mnt/share_data but it really doesn't matter.

And no you do not want to mount it to /usr but you could create a directory in /usr.

Welcome to linux. You can find lots of answers to your questions by just searching the website.

Indeed :-)

Many thanks

To make this clear as mud. If you are dual booting and want to share data between linux and windows use FAT32.