It greatly annoys me every time I read somewhere that Special Relativity deals with objects moving at constant speed and the generalisation of this is General Relativity which considers all kinds of motion. What's even more annoying is that you can find such nonsense written in all kinds of scientific literature, from lecture notes, to popular science to websites etc. This is, of course, ridiculous. Special relativity easily deals with 4-forces and accelerations (well, the second derivative of the position four-vector with respect to proper time), and so on. The correct distinction is that SR deals with non-gravitational physics in inertial reference frames. The generalisation of this to non-inertial reference frames is straightforward really (and this isn't GR): replacing [itex]\partial_x[/itex] with covariant derivatives and so on. However in doing so we see some terms appear in our equations of motion (which are related to the curvature tensor). What GR does is it associates these extra terms (and so the curvature tensor and it's various contractions) with the stress-energy tensor, and so finally solves the problem of gravitation in the relativistic limit, which is valid in all frames, inertial or not. Apologies for the rant, but it annoyed me enough and this has helped to vent my anger.