Reese, I have rods from 6' to 9'6" and I can say my favorite length rod are my 7' rods. At that length, I have three rods in bamboo, glass, and graphite. I can take a 7' 4wt rod and fish in almost any environment that I fish.
My 8' rods only have an advantage over my 7' rods in certain meadow streams...narrow streams, high grass banks, clear water, with wild spooky trout. In those streams a longer rod is an advantage where I must cast over the grass about 20' to a spooky trout...or, when I must hang the tip of the rod over a grassy bank to drop a fly on the water (and listen for a loud splash to set the hook). Below is one of the streams where I like to fish my 8' rod when the grass is high (that little white dot is my brother at the grass horizon).
Honestly, I fish my 8' rods less than any other length rod that I own and that's only because of the stream environments that I frequent. I probably fish my 7' and 7'6" rods the most because I'm on mountain creeks and streams with brushy banks and tree canopies more often than not. For me, the 8' rod is a specialty rod that I wish I could use more often because I like to fish with them very much. I don't think you would regret having an 8' in your quiver...