Kurzweil PC361 Keyboard Bag
I usually get ATA style hard cases for all my gear (would be always if touring instead of loading in & out myself). However, for this smaller keyboard, I went with the soft case.
It is well made, and provides both ease of carry and reasonable protection levels (doesn't hurt that it weighs less than the ATA case, either). I would prefer having the backpack straps completely removable, likek the carry strap, but that is a minor issue.
The large side pocket is convenient for pedals, cords, other small things.