you will get all kinds of answers to this question, because it really depends on your feet and their needs. All of us have different foot needs.
I have really weak arches, and if I wear shoes without adequate arch support (like lightweight tennis shoes--keds, simple, easy spirit, etc...) my arches ache beyond all reason and kill me! Crocs are the enemy of my feet! They are just too wide for my narrow foot, and don't offer enough support--believe me, I tried to jump on that crocs bandwagon, but got booted off quickly!
I can wear Mephisto tennis shoes because they have solid support and fit my narrow feet. I have a pair of Merrell sandals that are very plain Jane looking, but are the perfect disneyland sandals. The straps stay put all day, and the footbed and straps are so soft---they are like velvet. No blisters or slippery, sweaty feet. The soles are so suportive, yet have perfect cushioning for standing in long lines (unlike my old Birkenstock--which have good support but zero cushioning, and I was screaming bloody murder by the end of day one!). I have them in the "cement" color--which goes with everything and nothing:
http://www.shoebuy.com/merrell-via-iii/141825/328180
If I really want to hedge my bets against blisterage--I will wear a pair of high quality walking socks (you can buy them at comfort shoe shops) that say "anti-blister" on them---and wear them with those sandals. I know--supremely ugly, but happy feet make up for the uglies.
So I wear a combination of my perfectly ugly but perfect for Disneyland Merrell sandals, and Mephisto athletic tennis shoes. Works for my feet!