Quoted from Black_Knight:You are better off getting USD from an ATM than exchanging them with a person
I agree with this. I lived for 5 years in Germany (Hannover), and the one big difference is that in US, you don't really need to carry very much cash around. Almost everything can be paid for with a credit card including Restaurants, Taxi's, most things at ReplayFX, etc. To be honest, I rarely carry any cash on me.
I think pretty much all ATM's over here should take Cirrus so make sure your debit card works with that network and you should be ok.