I know everyone has different needs, but this is the best flight bag I have run across for me:
http://www.brightlinebags.com/ (http://www.brightlinebags.com/)
It has the most room for the compact size. I saw it and immediately bought it at the Heli-Expo conference and it has been great.
Depends how much stuff you want to carry. For me, it's all about compact size; I don't want to lug a bag on that's going to alter the CG, heh.
There's some good recommendations in the Flight Bag Recommendations (http://captalk.net/index.php?topic=2237.0) thread from way back when. I ended up getting just that David Clark headset bag recommended in there. I can slip in my headset, my logbooks, my kneeboard and accessories (E6B, flashlight, pens/pencils, two sectionals and a plotter) and still fit it all in there with no problems.