Bass is a valuable player: he can play defense, he can finish around the rim, and he's got a few good spot up shots he can hit. He's not a $15M player, but he's a guy that every team should like to have, a few positives, not too many negatives.
Terry is washed out, and was a terrible signing. No team should ever be stupid enough to trade for him. He is only going to get worse, and if the C's can't package him for something, should amnesty him (if that's still an option).
Lee could be good on the right team. The bottom line is that the coach, and the personalities on the team make a big difference in how the team plays. He's not Ray Allen, II. Okay. But he can definitely hit a J, and can play some defense. He could start on a Toronto/Phoenix/Charlotte type team, and would be an improvement on what they have out there, in most cases. He could be a valuable bench contributor to an "also ran" kind of second round playoff exit team (e.g. Chicago, New York). He still has value.