  In the light of the LHC, we revisit the implications of a fourth generation
of chiral matter. We identify a specific ensemble of particle masses and
mixings that are in agreement with all current experimental bounds as well as
minimize the contributions to electroweak precision observables. Higgs masses
between 115-315 (115-750) GeV are allowed by electroweak precision data at the
68% and 95% CL. Within this parameter space, there are dramatic effects on
Higgs phenomenology: production rates are enhanced, weak-boson-fusion channels
are suppressed, angular distributions are modified, and Higgs pairs can we
observed. We also identify exotic signals, such as Higgs decay to same-sign
dileptons. Finally, we estimate the upper bound on the cutoff scale from vacuum
stability and triviality.
