In manga, I like it when translators leave honorifics alone; keeping -chan and -san and -sama, instead of trying to translate them into English. Same goes for familial words like imouto and otouto, nii and nee, ka and to.
I also like it when translators leave words that most manga fans are used to untranslated. So I like to see untranslated hai, osu, omedetto and a few others.
How 'bout you?