Should I buy a 2nd, backup computer for p2p sharing?

I'm inexperienced:

Recently I was told by a tekkie that the smart thing to do would be to have a totally seperate computer for file sharing. I was told that I should dedicate that computer for file sharing and nothing else. This, they said, would be the best way of achieving total security in the somewhat risky world of Bittorrent. That makes a lot of sense to me especially when you consider that you can buy a laptop computer for right around 500 bucks, 3,034 krona, or 254 pounds. I have yet to go out and buy a new computer.

Do you think this is a good idea or do you think it's overkill in concert with paranoia, or somewhere inbetween the two extremes :

Note that I live in California, have high speed
cable with Time Warner and have zero experience
with p2p file sharing. I was going to post this at
suprbay.org, but their site appears to be alternating
between either being down or it downloads in super
super slow motion, even with high speed cable. :cry: