PCI Card vs. IMic Input, Music & Audio Hardware Options

I do video but I'm new to the world of audio.  I have a sweet but new g4 system that I use for video editing and I want to start digitially recording audio.  There's no audio-in port, only USB.  I was told I should get a PCI card - they recommended th Audiophile 24/96 (which, I can't figure out whether I need to also buy the Co2 box for converting betwen RCA and Optical digital formats). I'm going to test out a Sony pcm-m1 DAT recorder and I know that the digital feed requires a 7-pin cable (that needs to connect to the PCI card via coax plugs).  However, a friend of mine told me to think abou buying an iMic adapter and just putting the DAT in via analog plugs -- that it doesn't make a bad transfer.  Any thoughts, anybody?  And any other advice -- things I'm not thinking of?  Oh...I'm going to put the audio into Final Cut Pro.