I'm a "pouch-in-pocket" person, and I use the black OEM leather pouch that came with it. Mine fits great (some complained about it being too tight at first, maybe they fixed it). I applied BSE to the screen, the entire back, and the top front where it sticks out of the pouch. I did buy an official RIM indigo blue pouch with square metal logo on it for $30 but I sent that back because it was way too tight and pushed various keys when the phone was inserted.
BB 8900 Tmobile, Moto Droid Verizon