Depends partly on file system, RAM and block size.
One school of thought is that you are better off with PFs3 for about 92 GB partition limit, Ram and block size irrelevant.
The other is that you can go 2TB with the latest incarnation of fast filesystem but you might need hundreds of mb of RAM to validate it if there's an error, and you need a big block size.
Also depends a bit on controller and medium.
EDIT: Added word "partition" to explanation in bold.