I was a bit dismayed when the Lions took Pettigrew, as well. However, I read a little bit more (both on him and some of the probable logic behind taking him), and I'm not feeling so bad now. The kid is supposed to be a darned good blocker, which will give a big boost to the o-line and the running game. He's supposed to be a decent pair of hands, too.
While I wouldn't have minded Oher or Maualuga, they're both a bit flakey (from what I've read). Hopefully, the picks that were made will pan out.