I just picked up my 2LT Summit White w/ silver rally stripes on Saturday. I chose the grey interior. It lightens up the cabin and is a great contrast to the exterior.
If you go solid white exterior, the beige would be good, too. Black stripes? Black interior. Sorry, not an orange fan, but if it had orange stripes, I'd still do black. You can see pix of my car in "My Albums." No pix of interior, though - but trust me, it looks great!
It's a pretty unique combination (maybe I shouldn't be sharing this...
).