I think my favorite panel to come out of Aiiro No Kunoichi so far was when one of the main villains had his big debut:
(from this page, I actually drew more of him than showed up on-panel so here's the extended version, lol)
I also remember being really proud of this one, from one of the other main villains:
(from this page)
Looking back on them, there are definitely some improvements I could make on them, but I remember being really proud of them at the time and they still stick out to me, so I guess that's what counts, haha.