They look ok to me... Nothing amazing, but then again I wasn't really expecting anything to floor me.
They're fairly close to that image Durge slipped in but isn't there now... At least similar in style from what I recall, but that either was a fan-made or early version of it.
I think the ANH color should've been more "red" for Tatooine or something... The blue of ESB I like only because of the dominantly "cold" theme it had at first.
ROTJ Cover's nice with the green I thought. My favorite of the bunch.
I agree with you Matt about the droids and Chewy missing. Blah! I didn't see him, but Tarkin should be squeezed onto the ANH cover somewhere if he isn't. He's equally important in that one film.