That PC is plenty good. I run a much less speced machine and gets 16 channels to the inbuilt hard disc. (Admittedly through a very efficient RME Digiface card).
Assuming you already have the mics, what you need to add is sound card + mic pres + software. Here are my suggestions:
- the 828mkii is a quite decent sound card, I used to run one myself before gearmania took me. Eight channels may be a bit of overkill, but if yuo need them they are there. I cannot really say I love the mic pres though. They are useable as long as they are not cranked all the way up, and if you are planning on recording live shows they should suffice.
- mic pres, if you want more that two channels at a time, you need more mic pres. The sky is the limit there in price.
- software. I strongly suggest you look at the Samplitude series of software. The best bargain if you ask me is called Magix Music Studio deLuxe. It is the same sound machine as Samplitude (ie it sounds good and works good) and it allows you to burn finished CD-s from inside the application, not many other programs does the full cycle from recording/editing/mastering/CD-burning.
Ooh, by the way, find a rack case for the 828mkII, especially if you get extra mic preamps. They look much better without all the scratches and live longer as well.
Gunnar