Here's a thought: You see people spending a lot of time reducing their base weight -- dropping big cash on titanium pots, 800-fill-power down bags, etc. But then they stick all that gear into a 5 lb Gregory Reality pack or something. That's f-ing ridiculous!
Also: "My 25 lb load isn't the same as your 25 lb load." I'm an average-sized man with a fighting weight of about 170 lbs. If you're a tiny waif, or alternately a 6.5 foot monster, 25 lbs is going to affect you differently than it does me. So think about your total pack weight relative to your body mass.