Recently, a former student was asked in an interview, "What is the most significant achievement in the theory of strongly correlated electrons in the past decade?". He later asked me how I would have answered this question. We were both encouraged that we had the same answer....
The marriage of dynamical mean-field theory (DMFT) and density functional theory (DFT) based electronic structure calculations. This has given a qualitatively correct (and often quantitative) description of iso-structural phase transitions in cerium and plutonium and of the ground state of transition metal oxides.
A nice overview is in this recent preprint by Dieter Vollhardt.
A more detailed description is in Reviews of Modern Physics by Gabi Kotliar and collaborators.