OK, my take and to each his own. Yellowstone is our favorite park (remember GSM is automatically excluded). It is like 4 parks in one, and then GT is just a short drive, can almost lump in as same. Grand Canyon does not do that much for me, been there multiple times, and last time TO hiked down a ways. Its nice just never one of my tops. Been to Ranier a couple or three times, again, nice. TO loves it much more than I do. I will say this, if you get a room facing the mountain and wake up one morning when you can actually SEE the mountain (NOT a given) it is spectacular. Some nice hikes, beautiful flowers, vistas. Olympic -another 4 in 1. All I heard was Hurricane Ridge, OK, nice. Sol Duc again nice, some interesting hikes, nice. Ruby Beach, sort of disappointed - I think my expectations were unrealistic, still enjoyable. We stayed at Kalaloch Lodge at Ruby and somewhere in Sol Duc, cant remember the name of the lodge. But then the Hoh Rainforest!!! It was at the bottom of our list for things in Olympic and was I amazed! It was like a wonderland. I felt like I was in a Star Wars ewok forest. Ferns over my head, soft, misty, just ethereal! Absolute wonderland. Like I said, to each his own!!
TO prefers Zion, and yes, he has hiked to the top of Angels Landing. I did not even try, I felt I could do it physically, but with my acrophobia was afraid I would get to the bridge and freeze, which would spoil it for TO because then he would not have left me and.... I preferred Bryce, especially in the evening, again, I think I am in the minority. We loved Arches, just so interesting and a different kind of beauty. Canyonlands is right next to it. Just could not compare to Arches, too much the same thing only lesser. We have returned to Arches and will again this year but have never bothered returning to Canyonlands. Before we went to Capital Reef a good friend, whose opinion I respected and had lived in Jackson Hole, told me it was a drive through park. I think she was correct. Some very interesting things: Mormon cabin, petroglyphs, etc. but it is not an awe inspiring, I must return type thing for either of us. Yosemite will probably blow you away. It is much higher on TOs list than mine, and like I told you, it is my brothers home park and he loves it like we do the Smokies. (And I would never tell him it was not right up at the top of list of my all time favorites!) That said, I preferred the Wawona side, I think that is southern. Entering the park and coming up on Tunnel View is beautiful, as are the waterfalls. Tulome Meadows is nice too, but if you can only go once, go in the Spring when the falls are full. I think that is one piece of advice on which 99% of people would agree with me. Ones youve not mentioned that I loved: Big Bend, Lassen Volcanic, Black Canyon of the Gunnison, and Crater Lake. Oh heavens! Crater Lake is one of those awe inspiring parks for me. Loved everything and every minute. Im not crazy about any of the caves, thats I. Although I must admit Carlsbad I might return to visit. The only park I would say absolutely dont bother with is the one in Ohio, I think it is Cuyahoga. Went there with friends and all four of us thought it was an absolute waste of time and effort. Again, to each his own. Also I did not like Channel Islands. First, long story on getting there, getting into the park, getting out of the park, and returning to mainland...a lot of that is I, TO not too thrilled with those aspects either, although no where near as negative about it as I. But the park itself! Sheer nasty. Now understand we went in the Spring. But everything was covered in sea gull dung, literally. No place to sit, had taken a picnic lunch, could not eat it, got back to motel and went to their laundry and washed everything we had worn or had with us and took showers. I swear I took two showers when we got in the room. Took that much to even begin to feel clean. Now, remember, we probably were there the only time it was like that....sea gulls cant mate forever, but I have no intention or desire of ever returning to find out. Anyway, what it took to get on and off the boat at the cliffs would stop me anyway. I do think that has been improved since we were there though.
Like I said, my opinion. If you want pics of any park, almost any area of the park, let me know and Ill work on TO.
Edit: whoops! Great Sand Dunes -absolutely unreal. I did not know a place like that existed in North America! And Everglands, either section, and good for multiple visits (we have, TO loves it) and Dry Tortuga's - sort of a pain to get there, we rented a seaplane rather than going by boat, but for a once in a lifetime thing to see I think it was worth it. Flying in and seeing it from above is spectacular and the park itself is interesting. Went with friends on that one too and we all four loved it and were glad we had done it. As soon as I post this, Ill probably think of another one. We are so blessed to have the beauty in this country and the NPS to help preserve it.