All of the above except Bow Ashigaru, the mainstay of many an army for me. Bow Ashis with excpetional accuracy bonus (master bow maker + hunters lodge) are good enough and dirt cheap. They're not supposed to fight or get shot at, they're just supposed to hit things with arrows. Bow Samurai are too expensive, you're paying for melee abilities you will/should never use.

I've also never really used Imported Matchlock Ashigaru, since when I did try them out, they were incredibly underwhelming. They barely got a volley off, looked more like a few odd shots that didn't really kill anyone. Because of this I haven't used any gunpowder troops at all.