DailyComix works for me. I've noticed that choosing a comics app seems largely based on which comics one is interested in (since they all seem to have limited menus of webcomics that are supported).
Special note: if you're a fan of xkcd, try "
xkcd reader" (in the market) (by Srikanth Lingamneni). I usually don't like single-purpose apps but this one is worth it as it features panel by panel navigation in the correct order (which means there is probably some back-end coding involved for each comic). The end result is exquisite.
Edit: In retrospect, that's probably not the kind of comics you were talking about
. Still, I'll leave this here in case anyone's interested.