I bought two protective cases for my Nexus 4 few months ago… a Nilkin Hard Case and Soft TPU Gel Silicone Case.
I use Nilkin Hard Case just to show it off because it looks tough and thinner than Soft TPU Gel Silicone Case. But whenever I want to mix my unit with keys* and coins* inside my pocket, I use Soft TPU Gel Silicone Case. Coz it covers all corners for bumps and protect its screen when the unit is faced down. TPU also grips on lots of surface and with wont slip like Nilkin.
Most of the time… I use Soft TPU Gel Silicone Case because it stays inside my pocket more often ^_^ than showing it off ^_^.
I posted some pictures of “Nilkin” and “Soft TPU” for you to decide which case fits to your needs.
* I use XtremeGuard film to protect my screen and shiny back panel from scratches.