The most lasting set I have came across is an Ash set a friend made for me. Ash is the Sherman Tank of woods. It doesn't show scratches, it's probably a special order from the lumber store, and a bit more pricey than other more available woods.
Regardless of durability, I would not recommend Octogon kubbs. It changes the game too dramatically and you lose some of the "spirit" of the game in my opinion.
I would suggest something poplar. That is a solid wood, has the same weight/density as a Southern Yellow Pine (SYP) set, and lasts a little longer than Pine, which is a little more malleable and soft.
However, as Garrick probably has noticed, you can generally buy 2 SYP sets for the cost of one poplar set. so it may be a wash in the end.
Just my 2cents.