I typically use Gaussian filter or Mipmaps for large textures if need be.
a filter of .5 to 1 seems to work well.
Turning filtering off is actually kinda a bad idea as it does in fact make your textures sharper up close but results in bad artifacting as textures fade off in the distance to the vanishing point. Also it can cause a descent amount of noise if textures that pan across camera for instance.
Try rendering out at a higher res before hand certain 3d elements with filtering on, then downrez in your post applicaiton if need be.