When I unwrap a mesh, and put a UVMap over it, I get weird white lines where my seams are. Any reason for this?
The moment you hit F for UVFace mode it activates the TexFace property in F9, Mesh tab. That puts Vertex Paint on your object and the default color is white, so just vertex paint the seams to a color similar to the UVImage. Or you could UVMap it again and make sure you have the faces with seams overlapping a little.