You can remove some of the tiling effect by combining two photos.  Put one in channel A and another in B, then put a procedural in C (one of the cloud-ish ones, usually) then ctrl-click on C next to diffusion, ambience, etc.  Creates a more interesting texture, too.

Edit: Or you could cover the ground with so much stuff that no one can see it anymore, but that approach isn't for everyone ;)