You could build a 3TB SSD RAID. Of course, it would cost you nearly $3,000...
I'm very pro-SSD but I think most people misunderstand what they're really FOR. That tech is massive overkill for something like storing MP3s or Word/Excel documents, where retrieval speed doesn't matter very much. SSDs are great for installing your operating system, which makes the whole machine snappier and more responsive, because lots of files are read/written constantly while you work. Saving a few milliseconds in file retrieval time adds up, when you're talking system files. Shutdown/restart will be MUCH faster.
Putting your iTunes library, or any files you retrieve only a few times per session, on SSD is overkill -- which means a waste of money. Store your ordinary files on traditional hard drives. There's virtually no performance advantage to using SSDs for basic file retrieval. Use the SSD for system files only.
In the MacPro I'm using at the moment, there's a 128GB SSD with the system installed on it, plus a couple of TB of traditional internal SATA drives, plus another 8TB of external (NAS and firewire and USB) drives. The more frequently accessed files are on faster internal storage, and the less frequently accessed stuff is on cheaper, slower storage --- the inexpensiveness of this storage means everything can be backed up and redundant.
If I were helping someone specify a new machine to be used for a combination of media work and routine stuff like email/web, I'd say get a small SSD for the system (128GB or maybe 256GB to be safe), a big internal SATA hard drive for main file storage, and a big external drive for backup storage. You don't back up the SSD -- it's pointless, because you can always reinstall your system. Maybe once in a while save some of your important settings, like web browser favorites/bookmarks, or better yet, find ways of keeping these settings on the cloud, such as with Dropbox.