You obviously realize the definition of privacy, and you don't strictly state the material you're considering. After installing Miles of fencing in my life, and now in Florida... Privacy equates to two basic types of fencing. "Stockade" in 6ft high x 8ft long panels, BOARD ON BOARD (meaning an overlapping slat over two slats not butted together...OR the newer Vinyl/PVC fencing, often used in Tract developments.
Stockade here is usually Cypress, which is weather resistant, but will SILVER and decay. Obviously woods like RedWood, and Cedar would perhaps be longer lasting, but will be more pricey.
Another issue with most wood fencing, beyond the fact that the environment affects ANY, is that it's so often sold,especially at a bargain price, in a 3/8 thickness. TREATED would be a rare inclusion and/or an even more expensive option.
I realize this is lengthy, but Privacy could even equate to Chain link and Vine plants. You should shop dealers that strictly sell fence for all the various options; and realize that any might need some maintenance or replacement at some point.
Steven Wolf