Lots of love here for the Otterbox commuter.  I ordered one, and also a 3.00 TPU case from ebay (smoke/ argyle - because I like to have some style sometimes  

)  
Anyway I actually think the otterbox is a bit overrated(for the price)  I don't see it having much more protection than the TPU case from a drop/shock standpoint.  and the extra bulk is a bit much for me.   Also the access to the power port is a bit annoying for everyday use, especially if you use docks.
the TPU case I got is AWESOME(especially for 3 bucks).  Sleek, same corner/drop/shock protection as the Otterbox(commuter) in my opinion and it fits like a dream.    Yeah sure the otter has the plastic back, but most drops land on the corners and in those areas, its just thin silicone.   I'm no scientist so I could be way off here, but it just doesn't seem 30.00 better than a 3.00 TPU case.
What I have been doing is using the TPU around the house/office - and if I am going to be outside at a tailgate or something, or somewhere where I might drink alot (get clumsy), I throw on the commuter.  even though it seems like the difference in shock protection is negligible, the hard case back certainly adds some protection and also having the ports closed up is nice if you are in a dirty environment.  
That strategy seems to be working for me, but if you really are looking for protection over form, skip the commuter and get the defender series Otterbox.  Cut out the useless screen protector on it though, gorilla glass feels great and I can't scratch it if I tried.  And skip any screen protectors.  Even the best ones feel terrible compared to the gorilla glass.
Just so you know where I am coming from,  I like to keep the phones nice for resale so that's my main concern.  I do have insurance so breakage is a secondary concern.