Firewire, IEEE1394 and i.Link are all the same thing. Firewire cards shouldn't cost too much and many sound cards have them now too.
Computer screens quite often have a higher resolution than what you can get off of video or TV. When you try to watch it full screen, the computer just makes each pixel bigger, which is what makes it blocky. I don't know what resolution your camcorder uses though.
goates