What is the best method of taking currency to Berlin?

Take cash to get you started (bus/train tickets and initial eat and drink), about €100 in mixed value notes should be enough initially;

a debit card so that you can withdraw money from most ATMs (cashpoints) with the minimum of bank charges during your stay (don't withdraw less than €50 each time or the fixed charges become a high % of the cost);

and a credit card to pay the bigger bills like hotels, restaurants and anything that you buy in KaDeVe.

In a money belt. Best way ever. Wallets, etc. are easily stolen. The Germans use the Euro now, so you pick up Euros in most other European countries or order them from your bank. But try and use credit or debit cards. They are safer by far. Don't use travelers cheques any more.

Get your cash out of ATM's with your debit card when you get to Berlin.

i usually just usecash machines oh the Star or Plus banking networks