The main purpose of walls is to break mob line-of-sight (LOS). Mobs won't aggro if they can't see you or any base structures, they'll just wander around alerted outside. For this a stakewall is perfectly acceptable and I always plop down a stake wall around any portal I plan on leaving up permanently or semi-permanently.

As for taking hits, marble > stone > wood. Stone is easy and abundant. I like to make perimeter walls 3 tiles thick so I can hide workbenches and stonecutters inside the wall. The extra thickness also keep trolls from damaging things in your base (either because you built in black forest or "The ground is shaking" event is going). Log trolls can still hit a small area on the far side of a 3-tile wall though, so be at least a little vigilant.

Walls are useless against seekers, bats, and drakes. You have to deal with these events. I like to fight in a spot in base where they're not likely to cause a lot of collateral damage. Open spaces where you can spin around with an aegir and not hit any base structures, drakes aren't going to knock down your roof, same with seekers, etc.