I agree that we are going to need more info. My biggest question is what are you trying to record live? Is it a full standard rock band with a 5 piece kit or more, guitar(s), bass? Is it something more? Do you have horns? How many people are you trying to record at a time?
If you think you only need the 8 tracks, then there are a couple options open for you. I'd suggest some of the 8 track soundcard options. MOTU makes the 828 which I personally use and is great. It's also a bit $$. Check out its specs on the site. If your going the pro tools way, then you can check out some of the digidesign stuff, but I'm not too familiar with that stuff. Presonus makes the Firepod which is also an 8 track card. I'm not sure if the Firepod has ADAT lightpipe options like the MOTUs have. The lightpipe option is just a plus because you have the chance of adding more simultaneous live inputs later if you want. You can get the Firepod with Cubase LE now on zzsounds. One of the great things about the Firepod is that each channel already has 8 pres. M-Audio makes the Delta 1010, which I know a couple people have and love using. Not sure about Lightpipe options on that one also. This one is about $400 new at the cheapest I've seen. You can get it for $200 without the casing.
There are many other options besides firewire soundcards. I only suggest them because I have experience in that field and not too much in anything else. There are MANY other ways of doing this.
Good luck,
Ben
