I guess I can contribute to my own thread. ;)
This is both places I have been/would recommend and places I want to go, mostly in the PNW and basically just nature-y things rather than culture-y things.
Olympic National Forest/Park and surrounding area: Hurricane Ridge (grand views), Tubal Cain Trail (mines and a B-17 wreck), Mount Storm King, several Elwha and Crescent Lake trails, the rain forest (so. much. moss.). Many of the beaches both on the strait and on the coast (west of Port Angeles mostly, Ozette area on the coast,). Also there are several different parks with bunkers from WWII which you can explore.
Mt. St. Helens. You can hike up to the top. It's on my bucket list.
Some of the areas around Spokane (eastern Washington) and Northern Idaho. Beautiful views, though not as lush as the west side. Even just driving around through the orchard areas was fun.
National Glacier Park and surrounding areas. Frozen waterfalls. Sapphires. Bubbling mud. Etc. (Yellowstone is nice I guess, but I felt kind of "meh" about it.)
Columbia River/Gorge area-- so many beautiful hikes and falls (not just the renown Multnomah Falls), incredible vistas, and some really unique ones like where the whole trail is just a creek that you wade in the whole way until you get to a hidden pool (hidden in giant boulders).
Newberry Volcanic National Monument, in Eastern Oregon. The lava flows were my favourite. I want to go again and hike more of them. Speaking of volcanic, I also mildly enjoyed Craters of the Moon in Southern Idaho. Didn't seem like there was a whole lot to it (not sure if I missed something or if that was it as it was a drive-by occasion), but I find lava rocks to be so fascinating.
Bryce Canyon, Grand Canyon, Mesa Verde, and White Sands are some major tourist destinations that were extremely enjoyable/interesting despite the crush of humanity.
So yeah, there's the whole eastern half of the United States that I have yet to explore (especially interested in the East Coast and historical sites), most of Canada (have been to Vancouver a bit, but too long ago to appreciate it), and eventually I want to branch out to something more global. Europe and Australia have been peaking my interest lately, but that is not for years to come at this point.