If someone were making a network of workstations at a company that needed high performance from commodity hardware, what would be the best thing to use if they were starting from scratch?
Of course, if you mainly are using Hadoop you'll probably be playing around with HDFS.
If you just have lots of Data and need to process it, maybe Ceph.
If you need POSIX/NFS, you'll probably look at some sort of clustered NFS solution (a la GPFS).
You've also got Gluster and Lustre.
My general recommendation would probably be to examine Ceph first.
Edit: I was assuming you meant some sort of networked storage system, I didn't realize it was for workstations. My answers are probably super overkill for what you need.
Come on, I have seen 8 10k SCSI drives/RAID10 in a Windows 2000 box be used by "a couple hundred people". It wasn't great, but this setup would blow that away, esp. if the hosting machine as a decent amount of RAM (32 GB+).
Yes I was suggesting NFS + jumboframes.
For instance NFS is pretty poor if your use case is serving shared network directories for workstations (not really great with complex ACLs), or if you require proper authentication for the resources (the Achilles' heel of NFS - where's my kerberos support?!?!!). You might be better off with CIFS.
As the other comments already pointed out, there are several alternatives for several needs. Performance alone should not guide your selection.