Do you spend what may be a short amount of time that you have left on trying to build a foundation to give your wealth away, or do you spend it doing what you enjoy most? Jobs gets viciously and unfairly criticized on this point. If other people ('normal people') choose to pursue what they want to with their remaining time in the face of such a diagnosis, few would dare criticize them.
That becomes an even more important question when you realize that Jobs knew his wife would be fully capable of giving his wealth away after his passing. In the second half of his cancer battle, it was pretty obvious he was not going to survive longer term. So what do you do at 52 or 53 years of age, when it's apparent you're going to die? Do you spend years (which you may not have) trying to build a successful foundation? My personal opinion is that's an absurd premise. The reality is, we'll never know if Jobs would have become a successful philanthropist, or whether he would have focused on his work as Buffett has and leave the giving to eg his wife.
If Bill Gates had been diagnosed with a terminal cancer at 48, and died in his early to mid 50s - it's likely his legacy would look a lot different too. When Gates was 48 in 2003, his public reputation was far different than it is today, he was openly reviled as an abusive monopolist and robber baron with a long reputation for having been mean and abusive to employees.
It's Steve's vast billions that will be given away by Laurene, and he deserves a lot of credit for that, as much as someone like Warren Buffett does for the good his wealth will do. I don't see many examples of Jobs getting a comparable treatment versus what someone like Buffett does on this point however.
edit: if you care to, feel free to explain why you disagree with me, assuming it's not just based on a reflexive need to bash Steve Jobs and not give him credit for any of the good his wealth will do and or has done (while someone like Buffett gets a lot of credit, while performing almost none of the actual philanthropic effort either)