Try Bright Star by mowmo. Downloaded it from mobile9.com

It's pale grey and white, with lovely cobalt blue highlights. Currently its my daytimed theme (pleegoblue for night).

The onscreen keyboard is a bit dark. Otherwise its great - especially when modded with black plastic tweaks

*edit* I've just discovered that the onscreen kb can be changed as follows :

Add Star theme to Black Plastic menu
Activate Star theme
Switch to Black PLastic theme of your choice (allowing reboot between changes to occur)
Switch back to Star theme

Now the previous Black Plastic theme selected will have left it's onscreen kb behind, as it were, in the Star theme.

iPhonestyle lightgreen works well with this theme