i use the i5 dual core Mini as my Media Centre. I have about 10TB of pretty much every kind of media available (including large bitrate Bluray Rips 25GB+) it never breaks a sweat.
It can also handle mutlitasking very well (mine does have 10GB of RAM though which can be bought cheaply) i routinely have Safari open with half a dozen tabs, Mail, iCal, iTunes, a VPn client, Drobo Dashboard, Crashplan, Bitcasa, Dropbox, ps3 media server, Transmission and iStat Menus all running at the same time without any slowdown. I can run VMs in Virtualbox too with all this open too although my Windows 8 one does slow things down a little. Don't let people tell you the basic Mini isn't good enough for everyday use, it's a great little workhorse!
Also, your last post mentioned SSD. If you are used to having SSDs in your computers go for it. But a lot of people on this forum preach that a traditional HDD has no place inside a computer these days which isn't true at all. Don't let them convince you to spend more money than you have to, even with a 5400rpm drive the base Mini is perfectly usable without an SSD for everyday use.