I'm using this one and I feel like it will get the job done in the event of a fall.
I use this one. Works nicely.
http://www.amazon.com/gp/aw/d/B00FZ14E3S/ref=mp_s_a_1_3?qid=1415324478&sr=8-3&pi=SY200_QL40
I bought this case on Amazon (Matte Black) and it is seriously the best case I've ever had. I sometimes forget its even a case and think its part of the phone.
He didn't test the Diztronic case that shows as very highly rated on amazon for me, anyone know about that one at all?
Edit: this one
http://www.amazon.com/dp/B00FZ14E3S/ref=cm_sw_r_udp_awd_dZaGsb113T4A4
I'm going to start with a diztronic TPU: http://www.amazon.com/Diztronic-Matte-Black-Flexible-Nexus/dp/B00FZ14E3S/ref=sr_1_1?s=wireless&ie=UTF8&qid=1383757263&sr=1-1&keywords=diztronic+nexus+5
Looks simple and protective enough which is perfect for me...if I don't like it I may grab this one: http://www.amazon.com/Caseology-Finish-Flexible-Hybrid-Google/dp/B00FEBU1ZO/ref=sr_1_3?s=wireless&ie=UTF8&qid=1383757263&sr=1-3&keywords=diztronic+nexus+5
edti: spigen also has a bunch of different models that looks nice. Here's one: http://www.amazon.com/Non-Slip-Spigen-Japanese-Protector-Excellent/dp/B00EV8Y50S/ref=sr_1_2?s=wireless&ie=UTF8&qid=1384450194&sr=1-2&keywords=spigen+nexus+5
I have a Diztronic TPU slim case for my Galaxy Nexus and now have the version for the Nexus 5.
http://www.amazon.com/Diztronic-Matte-Black-Flexible-Nexus/dp/B00FZ14E3S/