Skewers weigh 9/10 of naff all, and they're not rotating mass, so they don't really matter anyway.
Comparing wheels isn't as simple as just comparing one weight to another. A low spoke count wheel will usually have a heavier rim, which is harder to accelerate but will maintain momentum better once up to speed. A high spoke count wheel will usually have a lighter rim, which accelerates quickly, but doesn't maintain as much momentum. Heavier hubs are usually stronger, have better bearings, etc. Hubs are smaller than rims, diameter wise, so rotating a hub that weighs the same as a rim is orders of magnitude easier, so if it's a choice between a heavy rim and a heavy hub, the hub is probably the better bet. There's a lot to consider between hubs, spoke count and rims.
All that being said, the Fulcrum 7s are probably better wheels than the Giant ones, but I'd venture that handbuilt wheels for the same money as the Fulcrums would be better. They may not be lighter, but depending on where the mass is, they may still perform better, depending on your style of riding, and they'll certainly be easier to maintain, repair, etc.
