Depends upon what you wantThe core duo is faster in the benchmarks. However, having owned both (Acer 5672 with the 1.63G Intel Core Duo and the HP dv6040us with the 1.6G Turion 64 x2), I find little difference when running my normal applications (which include MS Office, Elements, Corel PSP, and CAD applications). Games are more likely to benefit from the video chip set/GPU, so if that is your main focus, get the one with a better GPU (the Acer, with the Ati x1400 runs circles around the HP with the nvidia 7200).
Oh, I returned the Acer because it did not run some of the CAD s/w as well, and in many instances, the duo core was not used to it's full capabilities (the Turion x2 seems to work with all applications in duo mode). Also, there was the issue of heat - the x1400 with the T2300 ran much hotter (close to 105F) than the TL52 and 7200 (about 85F under the same conditions).
Build wise, the HP is much better (except that the Acer keyboard has better feel and layout for the right shift key). The HP scroll pad, touch controls for the volume and playback, standard remote, and finish are better. The Acer did have a nice 4 way scroll button, but the overall ergonomics goes to the HP.
So, if you want a gaming machine, perhaps the core duo with a solid GPU would be the first choise. If you want 64 bit windows (without having to get a CPU upgrade to the T7xxx core 2 duo), then the Turion 64 x2 processor would be the one to get. I like the AMD, but most on this forum would go with the intel core duo for gaming (remember, that is what the main topic of this forum is).
(who likes his dv6040)