I used my sandals (just a cheap general purpose pair) yesterday for the first time this year (last summer I did a lot of training in them because my feet got too hot in socks and shoes), and took them off for the final 1.5 miles. Today I wore shoes, but took them off when I was on easy grass and ran about 3 miles. I've just finished Born to Run and now realise how my running style changes without shoes.
Mandovark, I was intrigued by your DIY sandals, so I found Barefoot Ted's site, and will definitely order a pair.