Penn's biggest rival

Today I wrote a column about the Penn-Northwestern women's lacrosse rivalry. While it's certainly missing some elements of a classic rivalry (namely parity between the schools over a long period of time) it nonetheless has developed into Penn's best team's biggest rivalry.

But has it become the school's biggest rivalry? Considering the men's basketball hasn't played a truly meaningful game against Princeton since 2004, that rivalry certainly isn't at its height. Penn-Cornell has fast become a more important rivalry as Cornell has won the last two M. Hoops Ivy titles. In football, Penn-Cornell historically was a huge game, one that nearly rivaled (no pun intended) Harvard-Yale.

So I ask you, which of the following rivalries is the biggest currently at Penn:

Penn-Cornell Football
Penn-Cornell Basketball
Penn-Northwestern W. Lax
Penn-Princeton Basketball
Any other one you can think of?