Just to counter big_scot’s pov I’m a big advocate of lens filters (protection, UV or whatever).
As I’ve said before, I’ve been covered in enough mud, rain, snow, sweat, beer etc to want an extra layer of protection on my glass.
YMMV
Higher speed cards only really come into their own when you’re downloading from them (with the right card reader).
Nowt wrong with buying the fastest but I’d actually suggest spending your pennies on two of your chosen card size. What would you do if you lost that one big card?
As for bags, there’s waaaaay to much choice to be able to give a particular recommendations.