The trail from South Lake to Bishop Pass, is, in my opinion, the best trail in the Sierras (at least of the ones I've seen) outside Yosemite National Park: lots of lovely lakes and steep granity mountains, plus a view that constantly changes. The trail crosses the crest of the Sierras at Bishop Pass, at an elevation of 12,000 ft (where the air is thin!). One of the best things about the eastern Sierras, too, is that they are delightfully uncrowded compared with Yosemite and other major parks; you'll only rarely see people on trails like this, and no signs of civilization whatsoever except for the trail itself, so you really feel like you're in the middle of utter wilderness.