I had been using a moto centric 14L magnetic tank bag which I did like a lot. however, it did get all scratched up from my low-side. so while i didn't truly NEED a new one, i went looking anyway 
i tried moto centric's 19L one, but it was way too long in my opinion, so i sent it back.
i next tried First Gear's Silverstone tank bag (not the Silverstone 2, which is bigger, but the first one): http://www.firstgear-usa.com/Luggage/Silverstone/CSSTankBag.html
This one I will keep as I really like the fit on the NT.
The magnets in it are much stronger than the ones in the moto centrics, and as you can see in one of the pics, the magnetic ear flap fits perfectly on the metal of the tank. The problem I have seen with others is they often rest on the plastic covering. With all magnets on metal with this bag, I know it isn't going anywhere.
It is also expandable - a zipper on the bottom gives an inch or two of more vertical space as shown in one of the pics below.
It's not a large bag - maybe medium size, but I really like the fit on the bike. It doesn't interefere with the bars at all. And the color looks pretty good on the faster silver to boot!
It comes with a clear raincover. The plastic material is a bit thick so it doesn't pack too small. I'm sure it works fine, but I plan to use the cover to my old moto centric bag as it packs down really small to fit inside an inside pocket on the Silverstone.
edit: almost forgot: it comes with a strap on the top, and two on the bottom which i assume is to connect to an optional strap mount base. they just got in the way, so i cut them off. the bag also comes with a shoulder strap.
$80 at the superstore: http://www.motorcycle-superstore.com/1/4/71/2727/ITEM/Firstgear-Silverstone-Tank-Bag.aspx?WT.ac=SLIsearch
i tried moto centric's 19L one, but it was way too long in my opinion, so i sent it back.
i next tried First Gear's Silverstone tank bag (not the Silverstone 2, which is bigger, but the first one): http://www.firstgear-usa.com/Luggage/Silverstone/CSSTankBag.html
This one I will keep as I really like the fit on the NT.
The magnets in it are much stronger than the ones in the moto centrics, and as you can see in one of the pics, the magnetic ear flap fits perfectly on the metal of the tank. The problem I have seen with others is they often rest on the plastic covering. With all magnets on metal with this bag, I know it isn't going anywhere.
It is also expandable - a zipper on the bottom gives an inch or two of more vertical space as shown in one of the pics below.
It's not a large bag - maybe medium size, but I really like the fit on the bike. It doesn't interefere with the bars at all. And the color looks pretty good on the faster silver to boot!
It comes with a clear raincover. The plastic material is a bit thick so it doesn't pack too small. I'm sure it works fine, but I plan to use the cover to my old moto centric bag as it packs down really small to fit inside an inside pocket on the Silverstone.
edit: almost forgot: it comes with a strap on the top, and two on the bottom which i assume is to connect to an optional strap mount base. they just got in the way, so i cut them off. the bag also comes with a shoulder strap.
$80 at the superstore: http://www.motorcycle-superstore.com/1/4/71/2727/ITEM/Firstgear-Silverstone-Tank-Bag.aspx?WT.ac=SLIsearch
