Actually, on most of my trips now, I carry a solo load - even when I'm with others. When it's the Scouts, we divide them into partners, and the leaders each carry a full solo load in case we want (or need) to split into two groups to camp. When it's with my buddy, it's so we have the option of camping apart, or even taking off on our own for a day and meeting up later.

And you're right - with lightweight gear, I rarely carry more than 20 pounds.