I have a Mac Mini and I'm unsure about how best to connect my Korg Trinity. Obviously I'll need a midi-interface, but I'm unsure of the options.
Should I be looking for something simple, like a USB to MIDI lead, or perhaps a firewire to MIDI lead? Or do I need a larger device?

I'd like to record real instruments too - I have an acoustic & electric guitar. There's an audio in on the back of the Mac Mini but I assume it'd be better to have a single device to sit interface between my mac mini and any audio sources and MIDI devices.
I have Garage Band on the Mac mini. Will this be good enough to get the most out of the Korg Trinity, e.g. recording, editing effects, velocities, controlling the mix, etc... or would I need to pay for some better software? Back in the day, I used the onboard sequencer only but I don't think I have the patience for that any more.
Thanks for any tips!