My old one is finally shooting craps so it's soon time for an upgrade/update.

I edit as a hobby. I'm not looking for top of the line insane stuff, just something that will allow me to edit from my XH A1 withouth performance issues. I understand the whole MAC thing, but would rather stick with PC since I alreayd have Adobe Premiere. Shoot me some techy numbers to look for. Can I get by with a Duo processor or should I go Quad Core? I'm not too worried about internal hard drive space since I will be utilizing three external drives.