Everyone should see them, but many (especially people not from North America) don't have the oppurtunity to see them in person... so I thought I'd help them out.
Here's something I wrote for a school assignment about them.
The Grand Tetons loom over the countryside to the east like monarchs over their kingdom. They are a stunning natural symbol of power. Because of the geology leading to their formation, the surrounding land is relatively flat; there are no foothills. This contrast adds to the power of the scene. The calm lakes in the area, in turn, inspire in the onlooker a sense of placidity and serene peace that is enhanced by the contrast arising from juxtaposition with the mountains. The green pine forests stretching on for miles, and even covering the bases of the mountains, are awesome tributes to enduring life. The knowledge that a great variety of impressive wild life thrives just under the tree tops that are so readily viewed, but remains just out of sight, instills the visitor with a sense of mystery when he or she considers what animals may be just barely hidden beneath the leaves. During the spring and summer, minute trickles of melting ice from the tops of the mountains fall down the rocky faces to add a touch of subtle beauty to already beautiful Cascade Canyon. This canyon itself is a thing to marvel at. Across Jenny Lake, it winds back out of view into the mountains. The trees that flourish within it conceal multiple streams and many cataracts. The mountains themselves are stunning monuments to the supreme indomitability of nature. Their peaks are over seven thousand feet above the surrounding country side, and approximately half that height is above the tree line. Though there are many sections of the rocky face that show bare, many other sections of the mountains are cloaked in snow through the summer. During sunrise, the mountains appear dressed in royal purple or passionate red, the former of which is very well accented by a field of lupine, if one can find one to view the sight from. The clouds, which are not uncommon to be seen hovering around the lofty peaks become beautifully jeweled with amethysts and rubies at this time, and seem the monarchs’ crowns. And to watch the sun set behind the mountains to the second movement of Beethoven’s sonata for piano no. 23, “Appassionata,” is bliss. Another excellent view of the Tetons is with “Mormon Row” in the foreground. This was a settlement built by Mormons moving west for religious freedom. A few houses and barns remain. To see an old wooden barn as it catches the sun’s golden rays be dwarfed by such impressive mountains so far away is truly humbling. Also, in some areas, there is a treeless expanse known as the sage-brush flats, which provides a completely unobstructed view of the mountains. This is especially spectacular to see when the mountains are draped in a rainstorm, adding to the drama of the scene. Aside from this, there are other meadows where one may easily become enthralled by watching coyotes running around and pouncing on mice for their meals. Other wildlife include the rarely seen wolf packs, more common black bears, possibly with cubs, intimidating grizzly bears, more common than one may expect, big horn sheep if one is extremely fortunate, elk, two species of deer, black and white tale, and more. Beyond these terrestrial creatures soars the regal bald eagle. One may occasionally swoop down to snatch a fish out of the Snake River. It is truly a sight to see such a bird perched along the bank of the Snake River as one rafts down it. Said river is quite pleasing to see as well, lined as it is with forests. The calm waters reflect the sky almost perfectly. In conclusion, the grandeur of the Tetons can be exhibited by the fact that that this essay has been so extremely insufficient to convey it.
Here are some more photos. Note that I don't care about copyright at all.
This one's Mt. Moran, just north of the Tetons. If you can see the the Tetons, you can see Moran.
It's pretty cool... I've acutally been in that old house in the last one.
PS, that second one I posted is by FAR my favorite... it's the perfect combination of subtle beauty and grand majesty. I wish it were bigger.