like the article says, ANY grease will void the warranty, save the Shin Etsu stuff in the article.
this isn't new news, it has been known for quite some time. No real shock either, AMD is covering their own rear-ends with this.
I believe it is also teh case that if you buy a retail CPU, if you don't use the retail heatsink/pad, the warranty is voided... Will read the retail packaging legalese in a little while and update my post.
Mike
Update from "Warranty" statement with AMD retail processors (in this case, a Thoroughbred 2100+ Retail):
This Limited Warranty Shall be null and void if the AMD microprocessor which is the subject of this LImited Warranty is used with any heatsink/fan other than the one provided herewith
So the same case, if you buy a retail chip, using any other heatsink than the retail heatsink technically voids the warranty as well. Again, AMD covering their own butt's. No real shock here.