your 7mm-08 is a great all around calibre. I would run 140's in it if you can.
If you want to upgrade I would skip the 280ai (which i think is another great round) and move up to the 300 wsm, which will run heavier bullets better then the 280ai.
You already said you will get a brake so no worry about the recoil in the 300 wsm in a lighter weight rifle.
I own a 7mm-08 in a Kimber Montana with a 22" barrel and I am just building a 7 saum, which is ballistically very similar to the 280ai . My intended use my 7-08 is a lightweight bush /cut block rifle with most shots under 300 yards. The 7 Saum will run 168 to 180 gr bullets and be more of an open country rifle, 200 to 500 yards.
If I encountered a Grizzly I would feel comfortable with either rifle and bear spray.
