Thanks for all the comments!
Filax_666: i tried adding some movement to the legs, but it seemed too exagerate given the small size of the sprite (since wrinkles look to big, and the legs don't move that much when one's breathing). I did give a go at the head movement, though (see below).
crab2selout.png: Thanks for the kind words
. At this size, i came to the conclusion that motion would have to be pretty much with buffer shading and subtle transitions. I've played Metroid only for a while before, but i'll check out the sprites to see what they did over there. Interesting that you say that the idle anim won't be seen that much, i had a different point of view (but i usually stop and admire the animations in games, marvelling at how pretty the colors are. And then i catch a bullet.)
Firefly and Crazy Asian Gamer: see below.
Original - Head bob 1px up - Sub pixel head movement
I see where you're coming from with the head movement idea, and if it were a larger sprite i'd definitely apply it, but at this size, i think even a subtle movement in that area doesn't work very well. I still prefer the original version, i think i'll keep it.
Thanks for all the help people. Working on a run cicle now, will post a wip soon.