  We present O(g^4) calculations of both planar and non-planar Wilson loops for
various actions in the presence of sea quarks. In particular, the plaquette,
the static potential and the static self energy are calculated to this order
for massive Wilson, Sheikholeslami-Wohlert and Kogut-Susskind fermions,
including the mass and n_f dependence. The results can be used to obtain
alpha_{MS} and m_b(m_b) from lattice simulations. We compare our perturbative
calculations to simulation data of the static potential and report excellent
qualitative agreement with boosted perturbation theory predictions for
distances r<1/GeV. We are also able to resolve differences in the running of
the coupling between n_f=2 and n_f=0 static potentials. We compute perturbative
estimates of the ``beta-shifts'' of QCD with sea quarks, relative to the
quenched theory, which we find to agree within 10 % with non-perturbative
simulations. This is done by matching the respective static potentials at large
distances. The prospects of determining the QCD running coupling from low
energy hadron phenomenology in the near future are assessed. We obtain the
result $\Lambda^{(2)}_{\bar{MS}}r_0=0.69(15)$ for the two flavour QCD
Lambda-parameter from presently available lattice data where $r_0^{-1}\approx
400$ MeV and estimate $\alpha_{\bar{MS}}^{(5)}(m_Z)=0.1133(59)$.
