Since I pretty much have lived in Texas my whole life, my first "damn!" moment came when I went to SLC in Utah and saw mountains for the first time. My next "damn!" moment came while driving around Calgary and Banff. Then my next peaceful, "wow, that's beautiful" moment came while driving around northwest Arkansas in the Fall. I really would like to take a trip out West since most of my drives have been around Texas and to Oklahoma, Arkansas, Tennessee, and Kentucky. I really would like to check out the Santa Fe or the general New Mexico area next, but that drive west from Dallas seems like the most boring, miserable drive possible.
There's a double whammy with Utah if you like that look. I think Texas has a lot of varied and natural beauty, it's just for the distance it's more inconvenient unless you do the roadtrip, moving west kind of thing.
Mountains make for great scenery. Spoiler Add water and it really kicks ass. Spoiler Best scenery that doesn't need mountains (although parts do) might be the Florida Keys. Spoiler
Hwy 77 between Cameron and Waco in spring early summer when all the sun flowers are in bloom is pretty cool
