You're gonna want either USAA or Pen Fed.
USAA is great, it's the bank I use, and I usually get my pay a few days earlier than my classmates. Great customer service, but you've got to walk to Highland Falls in order to get to an ATM that won't charge you a fee.
Pen Fed is more convenient. There is a branch on post, and ATMs out the wazoo.
You want cash on hand, I'd go with Pen Fed. If you don't mind using a debit card, I'd go with USAA.
You can use the ATM in Grant Hall. USAA will reimburse the ATM fees.