  Advances in creating stable dipolar Bose systems, and ingenious box traps
have generated tremendous interest. Theory study of dipolar bosons at finite
temperature (T) has been limited. Motivated by these, we study 2D dipolar
bosons at arbitrary tilt angle, $\theta$, using finite-T random phase
approximation. We show that a comprehensive understanding of phases and
instabilities at non-zero T can be obtained on concurrently considering dipole
strength, density, temperature and $\theta$. We find the system to be in a
homogeneous non-condensed phase that undergoes a collapse transition at large
$\theta$, and a finite momentum instability, signaling a striped phase, at
large dipolar strength; there are important differences with the T=0 case. At T
= 0, BEC appears at critical dipolar strength, and at critical density. Our
predictions for polar molecule system, $^{41}K^{87}Rb$, and $^{166}Er$ may
provide tests of our results. Our approach may apply broadly to systems with
long-range, anisotropic interactions.
