I agree with jaguarskx. For Microsoft Office, CPU really doesn't matter unless you are doing heavy Excel or Access work. I do a lot with Word 2007 (working with 300+ page files at least an hour a day), and I can't tell the difference between a brand new i5-2500K (some times work at my buddy's house who's a gamer), and my old Pentium E2200 desktop and my old Core2Duo laptop.
My thought is if this is an office machine, I personally would go with an AMD Llano. That way, I know I got a decent video card for light gaming and such.