The IBM employee discount on my last iPad was perhaps 4%. Not big, but enough to pay most of the sales tax.
I believe the Apple Friends and Family discount on iPads has been 15%. That amounts to $110 on the rMini model I will purchase and for me is worth waiting for since my iPad 2 is working fine until then.
I thought that perhaps others on the list who had used this discount may be aware of when Apple typically makes new models available.