Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I am using a mini right now, and it was very easy to use. The setup was not difficult, unless you count the FTP access. Still working on it, although I think its more of my router than the mini itself.
 
If you have HD's laying around then you can't beat a Drobo. Its a bit pricey but the fact that you can use any HD combination for RAID like storage is just incredible.
 
For a cheap option, can you not connect another USB drive to your Time Capsule? I think :apple: refer to it as an "Air Disk" – I have linked a HD to my Airport Extreme and it works fine.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.