Not to morph the thread too far, but in Linux we have used XFS and Btrfs with great results. If I was worried about performance and storage capacity on Linux, I would consider XFS as it has a mature set of tools, has been integrated and kept up to date in the latest kernel and has few disadvantages that you would look at planning for a growing number of files. Btrfs has great promise but Oracle buying Sun has somewhat clouded the view of where this is going to go, but Oracle says they plan to keep going with it, so it is something to watch for. Our tests of it had amazing results, but it was difficult to configure.
For your reference:
ext4 is fairly common in linux but can be really difficult if some of your data corrupts, and in general if you are able to choose then go with something like XFS.
I am sure that people will have many views on this, because many of the 'journalling type of File Systems in Linux can be tunned up and made-workable. I don't intend to start a flame war about what File Systems would best help Debbie plan for the future, I am simply relaying that our experience with these two files systems has been very good with our databases, and file storage, retrieval, writes, and large scale deletes. As well low data corruption.