I keep my grain in the garage on a platform not near the doors where insects could find it still in the sacks. I keep the smaller bags in an old file cabinet in the same place in thick self sealing plastic bags. I have 4ea 50 lb sacks out all the time up on a shelf because I make my amber ale, German lager, German Hefeweisen with these (pilsner, 2 row, white wheat, 60L crystal, 15L crystal ). You can spend a fortune in plastic tubs and they take up lots of space too. As Duff said you can fit 25 LBS in a 6 gallon brew bucket so a 50 bag fits 2 ea perfectly. I split a bag of munich with a friend so my munich is in a brew bucket.
Edit: I have never seen any evidence of bugs around the grain but I am in there every day so I can keep an eye on it.