If you know your way around the sky and are handy with star charts and have a reasonably good observing site, you might really like the 25x100, although they are quite heavy and require heavy duty tripod and mount, and you should read up on that. Check the Cloudynights.com binoculars forum.
Oberwerk makes a 20x80 LW that's under four pounds I believe, although they're more expensive.
There are at least three brands of 15x70, under four pounds, under $200. I've read that the Oberwerks are the best. But if you only spend $70 or so on Barska or Celestron Skymaster 15x70, then you could spend the rest of the $200 on some smaller handheld ones, e.g., 10x50.
Happy shopping!
Ed Cannon - Austin, Texas, USA