Interesting top-5, that's for sure. Acting-wise I more or less gotta agree with you - I do like a lot of his movies, but not all have an interesting storyline (such as girl meets boy, boy meets girl, boy loses girl, boy finds girl again, boy kisses girl, happily ever after)...
I think James Dean inspired Elvis to a great extent and it shows in the respect that Elvis is usually the violent youth (the rebel), playing the role with this raw naturalism. It's hard finding an Elvis-movie without fights, as I may conclude that it's what boys are supposed to do with each other in America.
It's too bad Elvis wasn't allowed to do a lot of roles with some deeper meaning to 'em. The early 60's did bring 'Wild In The Country' and 'Flaming Star', but 'Girls! Girls! Girls!' and 'GI Blues' started the acting decline, although I'm seemingly unable to hate these movies.
I'm not so sure about his last few movies. They were supposed to be more serious, but sadly, I've never been able to see them myself.