We happily use SVN for SCM at work. Currently I\'ve got our binary assets in the same SVN repository as our code. SVN supports very large files (it transmits them \'streamily\
At my company, we use Documentum as a ECMS, managing lots (and I mean really lots) of binary files. Documentum (or other ECMS like Alfresco) are supposed to be the "right" solution to manage documents. Documentum supprots tagging and branching, and can expose files as WebDAV (so integration into your workflow can be more or lessa transparent).
That's the theory. In practice, we found Documentum slow, hard to configure and manage. And honestly, even if we have lots of documents, most of them are not larger than a few 100's Mo.
This answer more of what you should not do than what you should do ... sorry ...