Been running MCE on a CeleronD 320 (2.4) for over a year. Only one tuner, and just recently moved to a SATA drive. You really do not need a dual core, or any expensive CPU. I suggest 1gig of ram, but 512 worked for the first year for me. The best advise I can give you about using an Intel chip, is use an Intel Chipset motherboard. DO NOT USE VIA!. A CeleronD 320 is about $60 bucks and my Asus P4P800S-X was only $47. On the side, I use it as a game server.
No fanboy here, I just like to do things cheaply