RHIC has been the dominant player in heavy ion physics, producing tantalizing evidence in support of the entropy/viscocity formula from AdS/CFT. What's the potential of the LHC's Pb ion collsions? What can it achieve which RHIC can't? What measurements will be improved?
A lot of what the LHC hopes to achieve in this area is described in a paper by Carlos Salgado, so I'd suggest you take a look at that. In summary: