Getting name brand gets you longer warranty services. That could be important if you can't afford to replace it should it break.
I got a Dell with a 3 year full warranty. For about the same price, but I ended up with a 2.2 Core Duo, 2 GB RAM, an 8600GTX and 160GB hard drive. His might be more powerful, but if it breaks down in two years he doesn't get a new one like I would.
Worth it.