Firewalls - Since this is mostly a home pc forum, I wouldnt recommend spending much money on a firewall. There are several inexpensive software based firewalls that work extremely well. Tiny Firewall is one of them. PIX is overkill for any personal lan. Its learning curve is also very tight.
Spyware could be an addition to your post. I like SpyBot http://security.kolla.de/ but Adware is another great program http://www.cexx.org/adware.htm
Once you've installed a firewall head over to http://grc.com/ and run some of the tests published by Gibson. He is a pretty annoying guy but the tests are a pretty good source to make sure you've tighted down your box.
As for the PC tip - I think we tend to promote building your own. Cant beat the price and you will be able to get a more powerful PC at cheaper prices
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Good post - Glad to see you here.
... i dont exspect people who ask us questions know how to setup a pc from parts ... 