Having been in Moscow, I was flying back to the UK via Poland for a few days. I was passing through security in Poland and the young man looking at my bags became quite animated when he found the large wad of notes in my hand luggage. He was equally deflated when I told him they were Roubles and that they amounted to about €150 worth. Unfortunately Travelex had given me tiny denomination notes meaning I looked like Loadsamoney.
I vary the amount of cash depending on where I am. In Germany, hardly any restaurants take credit cards, in Oz credit cards are accepted everywhere, so for a two day trip to Germany I could have a €500 and for a two week trip to Oz I could carry about $500 – $750.
Personally, I hate carrying cash. Even on a personal level I will pay for things with a card wherever I can.