She did it - no doubt about it. I refer you to the following website who have analysed her statements:
http://www.eyesforlies.blogspot.com/2007/11/am anda-knox.html
Including her initial statement to the police:
"Patrick and Meredith were in Meredith's room while I stayed in the kitchen. I can't remember how long they were together in the room, but I can only say that at a certain point I heard Meredith screaming and I was scared so I covered my ears. After that, I don't remember everything, my head is very confused."
Regarding "not a shred of evidence" - how about Miss Knox's DNA on the murder weapon?