Favorite: Mawile and Mew Even the manliest of men can appreciate a little cuteness. There is such a thing as manliness overload.
Least: Sentret Completely useless. I think Game Freak specifically designed them to be used exclusively as HM slaves. Also, any NPC that uses them usually has a full team of 'em at really low levels. Not worth fighting, but you have to do it anyway.
my favorite pokemon...hard to say since I'm an eeveelution nuts. least favorite...hard to say again since some of them are so useless [not mentioning names, mostly since I cant remember off top of head and I havent use all of them yet].