SharePoint is very good at document sharing.
Documents generally follow a process for approval, have permissions, live in clusters... and these things lend themselves well to SharePoints document libraries.
However there are somethings that don't lend themselves well to living inside SharePoint... do you have a virtual hard drive (.vhd) file that you want to share with a workmate? Not such a good idea to try and put a 20GB file into SharePoint.
SharePoint can handle large files, and so can SQL Server behind it... but do you want your SQL Server bandwidth being saturated by such large files? Do you want your backup of SQL Server to hold copies of such large files multiple times?
I believe that there are a few Microsoft partners who offer the ability to disassociate file blobs from the SharePoint database, so that SharePoint can hold the metadata and a file system holds the actual files, and SharePoint simply becomes the gateway to manage access, permissions, and offer a centralised interface to files throughout an organisation. This would offer you the best of both worlds.
Right now though, I consider SharePoint ideal for documents, and I keep large files (that are not document centric) on Windows file shares.