  We present the first angle-resolved photoemission (ARPES) measurement of
Fermi Surface in the "misfit" cobaltate [Bi2Ba2O4].[CoO2]~2. This compound
contains the same triangular Co planes as Na cobaltates, but in a different 3D
environment. Our data establish the similarity of their electronic structure.
We propose that the peculiar lineshape of all cobaltates is of the
"peak-dip-hump" type, due to strong many-body effects. We detect a progressive
transfer of spectral weight from the quasiparticle feature near Ef to a broad
hump in misfit phases where Ba is replaced by Sr or Ca. This indicates stronger
many-body interactions in proximity of the band insulator regime, which we
attribute to the presence of unusual magnetic excitations.
