Hm you could have saved the original texture then just put them back but i'm really sure you haven't done that so what i have done do remove to original texture is to remove the .minecraft file in C:\Documents and Settings\Admin\Application Data\.minecraft\lib and then the jar file or if you use the World of Minecraft client to classic just remove remove the minecraft.jar file in the lib file you have downloaded to make the game work.

Delete the BIN folder!! This will not effects your saves