Computing Models and Data Challenges of the LHC experiments

<!--HTML-->The LHC experiments are undertaking various data-challenges in the run-up to completion of their computing models and the submission of the experiment and of the LHC Computing Grid (LCG), Technical Design Reports(TDR) in 2005. In this talk we summarize the current working models of the LHC Computing Models, identifying their similarities and differences. We summarize the results and status of the data challenges and identify critical areas still to be tested