Both HP's you linked to are nice. I've also had bad experience with HP, but they made it right by shipping me an upgraded replacement. Because of this, I will consider buying from them again and still recommend them because they make some of the best consumer laptops.
Since 7150M is integrated, it won't be able to play the latest greatest games. In fact, it will probably struggle to play games that are a few years old. It is, however, a newer integrated GPU (replacing the older Go 6150). But you probably won't notice a significant difference between the two.
It will be DX10 compatible (in that you can install DX10 and continue to use the card), but the new features of DX10 will not work with the card (as a fully DX10 compliant card can) since this is a DX9 generation card.
If you want dedicated graphics, nothing can beat the value of a Dell Vostro. So you might want to consider them too. A nicely equipped Vostro with top-of-the-line graphics can be had for under $800. Of course, they will never look at pretty as the Pavilions.
Good luck on your purchase!