Are you using OS X 10.6? If "yes" then you're out of luck. Updates in 10.6 have broken some of Maya's display operations. I guess all your objects appear grey?
One way to resolve this is to enable "Hardware Rendering". This should show your textures but you'll loose quite a bit of UI speed.
If you can roll back to 10.5.
Jacques
Poly-pushing on a '96 SGI O2