I'm considering buying an ADC Student Membership for $99 but I already have Mac OS X and xcode so I wondering if the hardware discount is worth it to have.
Does the discount affect prices on Macs a lot? If so, by how much?
You can access the ADC store here to see the discounts. Definitely worth it for high-end machines...discounts on lower-end machines are more comparable to EDU discounts and so may not be worth the membership fee. And remember that you can only receive one discount per lifetime as a student ADC members (additional discounts would require moving up to ADC Select or higher), so make it count.
You should also receive a free copy of Leopard after it ships, although not necessarily immediately upon release.