What to look for in new desktop?

[Disconnected]

I'm helping a friend pick out a new computer for poker only. His budget is $700. He plays up to 8 tables with PAHUD and PT. Other apps that would run simultaneously are Camtasia, Skype, AIM, and a browser, but I think that's about it. He wants a dual monitor capability, too (although only one for now).

So, since neither of us know too much about what to look for, first off, what are the key specs to look at when shopping around?

Thanks.