I'm pretty sure you have to pay income tax on any unemployment benefits. And the state/county doesn't withhold tax, so that next April 15th you might get an unpleasant bill.

Having 3-9 months of fixed expenses money in the bank is pretty liberating. You know it's there and available, so your attitude at work becomes less about "OMG how am I going to pay my bills if I lose this job" and more about actually accomplishing something.