I'm a bit surprised by the negative comments on wood posts. I guess it's a regional thing because I've had great luck with round wood posts in the ground. My soil is acidic red clay, my climate is humid with an average of almost 60 inches of rain in a year. It's not uncommon to get a few thunderstorms that drop 3 inches in an hour or two a few times a year. One inches of rain from a thunder storm is common.
In my experience, I've neve seen a wood post of any kind rotted out in the ground. In every case, the part that in the ground is always pristine. Almost brand new looking. The rot is always at ground level, where the water sits around the base of the post after it rains. Usually this is a low area that doesn't drain. When I replace these posts, I build up the soil or concrete so the water flows away from the post. In the last couple of years, I've removed several of my wood posts to change the location of my fence, and 100% of them where in perfect condition, even though some of them have been in the ground 20 years. Some have only been in the ground 10 years. They are also mixed between being set in concrete and packed dirt. The ones in dirt come out easier then pulling T posts. The ones in concrete take the most effort to get out.
All of my wood posts are round. The worse post for anything is a treated 4x4 because they twist and bend more then anything else. They used to be fine, but when all the changes happened to how they had to be made, they are no longer worth using. I'm not even comfortable with 4x6 treated posts for anything higher then a foot or two above grade.
For staples, I'm still hammering in the barbed staples. I looked at a few of the staple guns out there, but the barbed staples that I saw where not hot dipped galvanized, and they where thinner then the ones I'm hammering in manually. Some of them will only take smooth staples, which I believe are worthless.
To make it a little easier, I have a tool that holds the staple while I get them started. They staple fits into a slot, and after you place the staple, you hammer the tool until it's started. Something that surprised me was how important a good hammer is. I have several hammers, and I started out using a solid wood handles hammer. But my forearms started hurting so bad that I almost gave up, but then I tried my Bostic framing hammer with a rubber type handle for the gripping area, and all the pain I was having when hammering wasn't there.