[wingtsun]

I just bought this bag and it's absolutely superb. I won't bother doing a full review as there are plenty already out there. Here's one, for example:
 
http://milspecmonkey.com/weargear/packsbags/368-511-rush-moab-6
 
This bag, however, has a little secret that makes it the perfect small pack for portable audio enthusiast. At the top of the single shoulder strap there is a small zipped pouch. It's designed to hold a smart phone but there's plenty of room in there. Inside is a thick, tough elastic band which is absolutely perfect for holding a smart phone/MP3 player plus a headphone amp firmly in place. Take a look here:
 
Here's the pouch closed:
 
http://thirtyfivemill.com/?attachment_id=2880
 
Here's the pouch open showing the iPhone 5 and Predator inside:
 
http://thirtyfivemill.com/?attachment_id=2881
 
http://thirtyfivemill.com/?attachment_id=2882
 
You can't quite see in those pics but the elastic band is about two inches wide. What's brilliant is because that pouch effective sits on your shoulder when in use it's in the perfect place to just run your IEMs from on the fly.
 
Here's a link to a shop that sells them in the UK (no affiliation etc..)
 
http://www.heinnie.com/Bags-and-Wallets/5.11-Bags/Rush-MOAB-6/p-281-517-6528/