From extensive internet research, I have decided that the best lock for the value/security/weight is the Abus Granit 54 X-Plus.
The 9-inch one (230mm) weighs 3.3 lbs. Hard to find in the U.S. but you can and can get it shipped for about (best price i found) $100.
It is $25 more expensive than the best price NY fahgettaboudit lock (best price online is about $75).
Both the Abus 54 and the NYfahgettaboudit are highly secure (relative to their competitors) according to all the recent Cycling Mag tests. And while the ABUS is longer, it weighs more than 2 pounds less. I don't see it's length as a security disadvantage b/c it is supposedly not able to be leveraged open with conventional methods. Rather I see it as providing the flexibility to lock around larger objects and to ignore Sheldon's lock strategy (which some say invites dumb theft attempts and others say ignores the threat of cutting the rim with bolt cutters ) and lock the rim and frame.
You could also go with the Onguard Pitbull mini b/c it weighs about 2.2 pounds and is just as strong against leverage attacks and is $24 with an extra cable (best price online). However, it against power tools the Pitbull wasn't as good as the more expensive locks, while the ABUS required 2 separate powered cuts to free the bike. And it's small/less flexible like the Fahgettaboudit. I decided the weight and price were less important to me than security.
Note on my intended usage: I live in Manhattan and would never leave my bike outside overnight or for hours on end, but want the most peace of mind when I park my bike outside to grab a burrito or even sit down in a cafe. But I don't want to lug a chain.
Hope this helps. Any comments would be helpful to future readers.