BSA but only if it actually warrants one. Shoving two texture files and a mesh into a BSA is just a waste.
Our only goal should be that our mods are the less difficult for the users to install, not to avoid us some work.

ladyonthemoon, realize, there are also people who do not want "another" bsa file as they are approaching the 250 bsa file limit. Not hard to do at all if each texture or two are thrown in to a bsa. Of course, those users can always extract the files from the BSA and make their own, and I know they do, but the loose file version is just easier.