Hi there. One of those backpacks already mentioned might work, but I'd prefer a "normal" looking business bag. Any suggestions would be great. Here's my criteria:

REQUIRED:
-Fits under the vast majority of AISLE seats
-Even though it fits under Aisle seats, it will hold a bunch of stuff
-Specific place for a 15" laptop to be securely held
-Durable exterior (like ballistic nylon - do not want leather or leather-look)
-No Wheels
-Attaches to a wheeled bag easily (even if it's not designed to, some strap on this bag needs to be in the right spot to allow it to attach)
-Some big spaces and some small spaces well designed into the bag
-All of the stuff listed at the bottom of this post must fit easily with a little extra room for the occassional extra item I may have.
-Very durable - I travel 75%+

PREFER (nice but not necessary):
-TSA Friendly flip-open style
-Traditional business style bag as opposed to backpack
-Exterior place for a bottle of water would be great.

MY TYPICAL PACKING:
- 15" laptop & power supply
- 2.5" external hard drive
- GPS with vehicle mount and cord
- Bose Quietcomfort 2 Headphones
- Asus USB Headset (for my virtual Cisco IP Phone)
- Phone / iphone / GPS charger
- 3 or 4 magazines
- A few files
- Small office supplies (pens, a little paper, pad, etc)
- My 1qt ziplock back goes in here for easy access

Thoughts on this would be appreciated.