Well, Giddens has a reputation as a knucklehead. If talent and athleticism alone were enough, Greg Minor, Gerald Green and Kedrick Brown would still be in the league. In fact, Giddens game reminds me quite a bit of Greg Minor.
If Giddens gets his head together and learns to shoot free throws, he could be a valuable addition. He has the talent to become a solid starter when Ray Allen rides into the sunset. If not, he'll be playing for Dynamo Moscow or Armani Jeans after his 3-year rookie guarantee expires.
I also think Chalmers has the ability to be a starting pf in the NBA. Very heady player. As for CDR, well, he can score, but you would probably have to hide him in a zone. Giddens appears to be a much better one-on-one defender.