After seeing someone post a pic of this sling bag on another forum, I thought I'd check it out for myself. I got it for $8 at my local Wal-Mart.
This is a pretty good sized bag. The interior of it can hold a PCDP, a few CDs, a bottle of water and other small odds and ends.
I'm not planning on using the small atachable strap case that was included with my purchase. Instead I just slipped my Case Logic MPC2 MD case on the strap. The included case is too small to fit my MZ-E710.
The interior has four fabric slots for CDs. I fit in a few ATRAC3Plus CDs there for my PCDP. There's also a pocket behind the CD area for extra minidiscs, papers, bus tickets, etc.
Finally I'll show you the area where the D-NE900 goes. This fits my CD player just fine, and there's a port just above the CD player for you to fit your remote or headphone cord through.
There is ample room in the bag for extras like a bottle of water, Clif bars, etc. This seems like it'll be a good bag to use while commuting or hiking. I dunno why, but I'm obssessed with getting the perfect carrying solution for my gear.