I like peaceful, white walls, so my sims have to as well. Here is a set of 10 walls for every room in the house - paint, panelling, tiling and combinations. All walls are very reasonably priced at just 3 simoleons each!

Wall 1 - full panelling - located in panelling
Wall 2 - 2/3 tiles, 1/3 panelling - located in tiling
Wall 3 - full paint - located in paint
Wall 4 - 2/3 panelling, 1/3 paint - located in panelling
Wall 5 - full tiles - located in tiling
Wall 6 - 2/3 tiles, 1/3 paint - located in tiling
Wall 7 - 1/3 tiles, 2/3 panelling - located in tiling
Wall 8 - 1/3 panelling, 2/3 paint - located in panelling
Wall 9 - 2/3 tiles, 1/3 panelling - located in tiling
Wall 10 - 2/3 tiles, 1/3 paint (no rail) - located in tiling

Panelling and kick/rail/crown are Maxis textures.