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 180
I have been thinking about them for around town, but they might make a good camp shoe.

Some other ideas for minimalist shoes: