When the LHC comes online in the near future, it's expected that we'll see a whole new realm of HEP. I'm curious why we actually believe this is true. For example, Kaluza-Klein inspired theories use the TeV scale as an a priori condition for their phenomenological predictions. The recent surge of unparticle physics papers does likewise. There is no obvious reason to set this scale, however. What theories (SUSY, string-inspired, LQG, etc...), aside from Higgs, conclusively pinpoint the TeV scale as the place to look for new physics (in the same way that the W and Z were successfully predicted to appear)?