8/14/10 Update. I've gotta pull my recommendation of these sandals. The reason: foot odor. Mind you I don't have a foot odor problem, but my feet smell with these sandals. The inner soles say "anti odor anatomic footbed" but that doesn't prevent my problem. I don't understand why since these Newports are pretty well ventilated. The only time I've had a foot odor problem was when I wore some waterproof (and non ventilated) Rockport shoes. My feet got really hot in those, which caused the foot odor after a while. Since I didn't buy these at REI, I'll have to keep them. I'll wear them while bicycling, but I'll try not to walk with them so much.
Summer's here and I doing more casual riding. By this I mean going to the grocery store, ATM machine, ice cream or coffee shop. I had been doing this with my running sneakers, but when you ride in the summer your feet can get hot quickly. This made me look for some sandals so I could get some air circulation/coolness in my feet. However, all the sandals I saw provided inadequate protection for my toes.
Basically, all sandals "expose" your toes. They all come with some straps around the other parts of your feet to keep them in place. And, I'm not about to wear flip flops because they look and feel flimsy. I'm kinda sensitive to protecting my toes since I severely mashed my "index" toe while riding a cruiser with flip flops as a kid.
I was familiar with Keen Newports but I had dismissed them a few years ago because they were a little fugly. I never saw them as a biking shoe/sandal. As I thought more protecting my toes, the only sandals that seemed to offer what I was looking for were the Keen Newports. They have this really strong rubber toe box/cap, which I like. The sandals offer plenty of cross ventilation. They look very well made as their stitching looks strong.
The negatives I have with them are that: 1) they're still not that strong in the looks department, 2) The insoles are hard; I wish they had cushier, softer insoles and 3) they're slightly heavier than your basic sandals. There are some reviews out there that say that Keen Newports are the most comfortable sandals ever made. I wouldn't go that far, though.
Anyway, if you're looking for some summer sandals that can protect your toes while biking, I would consider the Keen Newports. (Tag: Review of Keen Newport Sandals)