Just got to experience Yosemite and it is unbelievable. Every time I stopped to soak up a view, I'd go another 100 yards and get a better one. I did a comparatively difficult hike (full Mist Trail), but you can also just enjoy the flat walks in the valley or drive to Glacier Point for an easy hike/great views (which I didn't get to do). The drive in through Tioga Pass (closed in winter) was breathtaking too. Much like Grand Canyon, pictures just don't capture it. And if you don't like crowds, you can go to any of the more secluded areas/trails/campgrounds and do your own thing. The whole park is the size of Rhode Island.
Did Tahoe on the trip which is fantastic as well (the scenic drive around the lake is phenomenal) and if you are outdoorsy, you can either go off the beaten path or take a gondola up to go hiking at almost 10,000 feet. The top of the gondola is touristy, but the hikes were pretty quiet. There's also casinos, shows, quaint villages, cruises, etc.
I also - purely by accident - found a great little town called Mammoth Lakes an hour south (I just needed a place to stay that shortened the drive the next day) which is a sportsman's paradise - hiking, fishing, boating, mountain biking, skiing in winter. A whole series of small secluded mountain lakes 8000 feet and up (the lakes aren't mammoth, the town is named after Mammoth Mountain to the west). I was too tired after hiking in Tahoe and Yosemite to do much of anything other than drive around, but it is beautiful and a much less touristy place than, say, Tahoe. I'm going to try to go back to hike the mountain crest there next summer.