The most comfortable pack weight would be 0.0 lbs. That aside, I'm 5'11" 155 lbs. For me 20lbs in a pack with a functional hip belt is something I can just about ignore. 30 lbs I know it's there but it doesn't slow me down much. 50 lbs slows my pace and makes me want to stop a lot. Anything over 50 is just oppressive.