Thats an important issue you touched on marshy, although due to Agger's well documented metatarsel problems and the horribly inconsistent form of our full backs it has been difficult to retain a settled back four...hence him playing a right back at left back (Abeloa) and even playing our best centre half (JC) at full back.
Two full backs are an essential purchase in the summer if we are to progress as imo riise,aurelio, finnan and arbeloa are decent players in their own right but not good enough for Liverpool to progress to a higher level.
Seth, spot on....Insua is class(at least potentially) I cannot understand why he has not been included more on 1st team duty...