I really don't like either Redd or Carter for this team. They both need the ball to be effective, and neither is the dominant defensive stopper we are sorely lacking.
Let's look at the primary perimeter scores on the teams we are most likely to have to go through during the playoffs:
Pistons - Allen Iverson 6'0" / TaShaun Prince 6'9"
Celtics - Paul Pierce 6'7"
Orlando - Hedo Turkoglu 6'10"
Atlanta - Joe Johnson 6'7"
Lakers - Kobe Bryant 6'6"
Houston - Tracy McGrady 6'8"
With the exception of Iverson, these are all oversize 2s and 3s. VC or Michael Redd are greatly outsized, and cannot match up against any of these players, forcing us to use LeBron as a primary defensive stopper, which, even given the offensive capabilities of VC/Redd will limit the much greater possible offensive contributions of LBJ.
That's why I'd like to grab Gerald Wallace to play 2/3 alongside LeBron. Although we might have an issue against smaller 2s during the regular season (which we really don't have to worry about), those players don't exist among the teams we are likely to encounter during the playoffs. Gerald Wallace, with the ability to guard 2/4 can guard everybody on this list besides Iverson (who Mo Williams will be matched up against anyway).
Wallace isn't going to provide the offensive spark of VC/Redd, but he's certainly another threat. But with his amazing athletic ability, defensive willingness, and almost a year of Mike Brown coaching, he can be the piece we need to shut down our opponents #1 and allow LBJ to concentrate on the offensive end.
~Lyuokdea