I would personally take about £100 in Euro's, and £100ish in cash or Traveller's cheques. The Euro's so I would have some readily available spending money for taxi's etc. when I get off the plane ( in case the ATM's are not working ), and the cash ( or Traveller's cheques ) as a back-up if I lose my cards. Once there I'd just use my Nationwide debit/credit cards which are of course free at ATM's.
Horses for courses this really. I'm sure individuals have their own preferences, and priorities.