Hi,
Colour choice is a personal thing really. I think black/w black interior is neat but the constant cleaning is a drag!! I have Desert Silver with Oyster leather--the Silver sort of changes from a silvery colour to almost gold but, most important--it does not show the dirt! So, if I am busy, I dont feel I am driving a dirty car. The C230 looks good also in regular silver & any shade of red or maroon. Blue looks odd to me on this style car. Pick an interior which matches the car colour too. I find the leather seating is more grippy and looks richer(costs more too), than cloth.
Happy shopping.
Al