DE Jason Babin was the 27th pick in the 2004 NFL draft. He was traded to the Seahawks for Boulware. I remember there were a lot of people upset about his leaving the area because he was performing VERY well. In fact, according to Rustshack, some people were saying he was traded because he was outperforming Mario Williams and they didn't want people talking about him being a bust. The Texans were under a lot of pressure to take Vince Young or Reggie Bush that year and they ended up with Williams. I'd say they made the right choice.
The Texans tried to convert him to a LB. That didn't work too well. He hasn't had a great career up to this point and was lost in the shuffle the last couple years. But, he got back in shape and made some noise during the summer and preseason for the Seahawks. He was cut after the first week and has been trying to land somewhere. But, now that he's in great condition again, the Titans, Saints and Chiefs were really trying to get him signed. He ultimately signed with the Chiefs because he could probably start immediately with the injuries to Turk and Hali.
Also, the Chiefs signed LB Kyle Shotwell. Apparently, he's spent some time with the Bucs this season. He's a rookie out of Cal-Poly.