I personally like my Intel Core Duo in my notebook, it's a very fast CPU for 1.66 GHz, runs windows smoothly, my apps run great, most my games run flawlessly on it.
My AMD Athlon 64, a bit outdated, also does a wonderful job, 3200+ Socket 754, really tough to decide which to get... But if I were to build a new system, it'd be AMD. They are cheaper