Kings Canyon and Sequoia National parks in California have to be one of the most magnificent places on earth. I spent some of the summers of my childhood in this areas so maybe I'm biased, but I would say I prefer them to Yosemite, which i think has more visitors. We only spent 1.5 days here, but could have spent more. We did little hiking (nothing more than an 1 hour at a time) and some of the areas I wanted to visit were blocked off. We did however get to see the largest living thing in the world, General Sherman.
Grant Grove Cabins, inside the park. We stayed in the Camp Cabins.
Sequoia and Kings Canyon National Park, California
Giant Forest and The Big Trees Trail
Check out General Sherman
Climb Moro Rock (we didn't get a chance this trip, but I did in 1997)