I like my new Nike running shoes. I wore them on the treadmill for a couple miles on Monday, then changed back into my "old" Brooks shoes and they felt so tight on my feet. No blisters that day. I ran 7 miles with a friend today and I now have 4 blisters. So, I'm thinking it's the socks. I switched to Thorlos Experia socks sometime before my half marathon in March. I don't recall having the blister problem right away, but maybe it's the combo of the socks + heat that isn't working for me. So... what socks do you wear? Maybe I should have tried new socks before new shoes... running socks are expensive, but not as expensive as the shoes!