Mei-chan no shitsuji is another great butler manga - don't want to ruin the plot, but the protagonist's butler is the best of the best and takes care of everything for her. The main difference (other than age between butler and protagonist) is the fighting that is involved - her butler is a bodyguard as well. Great manga!
shitsuji-sama is an excellent manga where boy methis down to earth girl which is a refreshing change for him. He becomes her butler and is an amazing one at that. Excellent story, great art!
The story is very similar. A butler/knight who wants to protect a regular girl who become an heir thanks to her grandfather who find her after the dead of her parents. The both mangas are cute and cool :)