Agree Bigmick's point about defending Agger.
I'm not a coach, nor an expert in football, just a supporter. But one of my universal truths is that great centre backs have more than 200 games in their pockets, and the only way to have 200 games in the pocket is to give the lads GAMES.
"We have no time for that" some might argue. But in the case of Agger, I feel it's worth the try, as I think he'll be one of the best in the future.
You only can reach Cannavaro (great CB), Gabriel Milito (good point Lando) or Carraguer's level with experience. In fact, experience is the most valuable of things a centre back can have.
Woodgate is a centreback I like. He's injury prone, right, but that's a bit of a lottery. Meaning that I've seen players coming to clubs saying "Injuries respected me in my career", and have a big one at their 29. I have seen aswell injury prone players who at some point won't have more troubles. I woudn't discard Woodgate just because of that. I think he's quality.
It's the same case as Milito. Turned down by Madrid because apparently his knee was prone to injury -- rumour has it that he was turned down for not being "hollywood"-esque enough. No injuries in Zaragoza, great performances.
Other than Milito, and Ayala. Don't look to the Spanish Peninsula when you seek centre backs. Just the same way I think most EPL midfielders are shíte (with all due respect), I think that the level of centrebacks and defenders is much better in the English premier League.