I'm wearing Crocs at the moment and these are really comfie, don't make my feet sweat and are fully washable:
http://www.crocs.co.uk/crocs-crocband/11016,en_GB,pd.html?cid=22Y&cgid=women-collection-crocband
You can flip the strap forward or use it at the back.
I have arthritis virtually everywhere and can't abide anything too restrictive - these are so comfie.
They do more conventional looking ones as well in the same shock absorbing material - I've got some pairs that I've had 3 years and they are still going strong... not even worn or dinged.
