ES7 all the way! Much more balanced than the K81 and more refined than the SJ5.
If you can't afford the ES7s then you have a choice. If you love lots of bass, go for the K81. If you don't love lots of bass, go for the SJ5.
To "tomjonesrocks": You (apparently) have one of the best portables, the HD25. Why are you making silly comments like that? "the others are mainly purchased" because not everyone likes the sound signature of the K81 (...bass...). Try to describe, even vaguely, the relative sound signatures of the three (if you've heard them of course), which would be a lot more helpful than searching through "a million" threads. Or at least point the OP to some comparative threads/posts. Have you tried searching for relavant info on the K81s? Its not easy, they're recommended in many threads, often with no extra description other than "they rock"...