  Over the past decades, several ideas and technologies have been developed to
directly detect WIMP from the galactic halo. All these detection strategies
share the common goal of discriminating a WIMP signal from the residual
backgrounds. By directly detecting WIMPs, one can measure some or all of the
observables associated to each nuclear recoil candidates, such as their energy
and direction. In this study, we compare and examine the discovery potentials
of each readout strategies from counting only (bubble chambers) to directional
detectors (Time Projection Chambers) with 1d-, 2d-, and 3d-sensitivity. Using a
profile likelihood analysis, we show that, in the case of a large and
irreducible background contamination characterized by an energy distribution
similar to the expected WIMP signal, directional information can improve the
sensitivity of the experiment by several orders of magnitude. We also found
that 1d directional detection is only less effective than a full 3d directional
sensitivity by about a factor of 3, or 10 if we assume no sense recognition,
still improving by a factor of 2 or more if only the energy of the events is
being measured.
