I disagree profoundly with he traditional view of block time for two reasons.
Firstly, it is simply not true to say that 'In Einstein's general theory of relativity time isn't even that special: it's just one of the four dimensions of spacetime'. One of he most fundamental formulae in GR is the formula for what is called the 'interval' S between two events. ('Interval' is to spacetime what 'distance apart' is to space) The formula can be written like this:
S = sqrt(x^2 + y^2 + z^2 - (ct)^2)
The minus sign makes it immediately clear that the temporal dimension (t) is quite different from the spatial dimensions (x, y and z).
Secondly, it is not possible to say that, because of the symmetry of all the known laws of physics, 'it's just as valid for time to pass backwards as forwards'. I entirely agree with Cortes here that the randomness built in to quantum mechanics proves that the future is indetermimate i.e. it 'hasn't happened yet'. If you subscribe to the 'bock universe' view you have a serious problem explaining why some photons are reflected and some photons are transmitted at a half silvered mirror because, in a block universe, nothing happens at random because the future is already fixed. The conventional interpretation of QM (the Copenhagen interpretation) allows for quantum events to be truly random and is therefore incompatible with the Block universe'.