Juri, E.ryu or guy.
Juri for sure. It’s the most all purpose button I know of.
Gouken. Great range and safe.
Makoto’s sMP takes that trophy I think. You can use her sMP for EVERYTHING. Anti air, anti dive kick, whiff punish, poke, frame trap, hit confirm, max damage combos, slicing vegetables, soaking up spills, it does it all.
Juri’s s.mk does all that (well, the max combo and hit confirm parts only in U1) AND it can armor break 
Hitbox on Juri’s farMK isn’t nearly as good as Makoto’s except on the first active frame. Also remember, Makoto’s sMP is way safer and more active it’s 5/7/7 +2/+5 while Juri’s 5/5/14 -4/-1. Also Makoto’s sMP isn’t range specific AND it has such a crazy hitbox during all 7F that I’ve had it anti air a crossup before.
Gouken clearly. Amazing range. Such a good anti air.