Edit: The Silthilar Muscles/Bones/Tendons increase Strength/Constitution/Dexterity instead of just providing a bonus but they are outrageously expensive so its debatable how good they are.
If you don't work under WBL, or you can craft them yourself with stupidly-stupid price reductions, they're awesome. Pluses to all the Physical stats, initiative, fast healing, are all worth it if you're paying about 1/4th the price they charge.
As to which grafts to take: the fiendish wings grafts (I'm partial to feathered, but that's an aesthetic thing) are always good if you can't already fly. Some of the arm/leg grafts can get you cheap inherent bonuses and/or natural attacks. I would avoid the draconic grafts, since they have actual penalties and most of them, well, suck.