I also just loosen up my travel runners. I tried the aqua sprinter and hated them. They wore out quickly and I found gave a fail sense of protection. I would rather go barefoot.
I have thought about trying some grip socks http://www.sandsocks.net/product.cfm?action=show_product&product_id=34
but haven't yet. Someone on one of the backpacking forums I read seemed to like them a lot.
Another croc like alternative are the inov-8 recolite 180http://inov-8.com/Products-Detail.asp?PG=PG1&L=27&P=5050973081
I have been thinking about them for around town, but they might make a good camp shoe.
Some other ideas for minimalist shoes:http://www.adventureinprogress.com/tcfmf-selecting-footwear