If you believed in "supporting higher education", there are probably better ways than supporting the one exclusive blue-blood institution you happened to attend ...
If you truly want to support higher education, your best bet is to refuse to donate until the colleges cut their wasteful spending and lower tuition. This is doubly true for private universities. When they call asking for money, tell them why they're not getting any. Nothing will change until the money stops flowing.
Your self interest lies in it making your resume better. If you and all your class gave say 10% of your income to your school, maybe new students would graduate knowing more and make you look good. Or maybe the school gets bigger TVs and a better football coach.
That's not how academia works, at least at a public school. Administrators rarely get raises, and get pay cuts whenever the economy gets bad. This is why administrators are frequently overpaid when first hired, because they know that it's close to their earnings ceiling. If you want to get more income as an administrator, you have to move to a new job.
No, that money is going to athletics for bigger telescreens and not for student athletes. Ever since the Larry Vanderhoef chancellery, Davis has been spending more and more on athletics, with little to show for it.
I just wish Emil Mrak was still around as chancellor -- that guy was awesome. He managed to keep students from massive protests at UCD during the free speech movement era by shipping them in free buses to protest at UCSB, and he introduced all of the bicycle infrastructure in Davis. Instead, we have a profiteer running the campus, in cahoots with the nation's former top cop.