The all-round best line of wood-cased pencils is the Mitsubishi Hi-Uni. The Tombow Mono 100 series was a consistent second, but I heard quality changed after moving production out of Japan. Some people like the Faber-Castell 9000 series because its hardest grades are smoother than other brands. The Staedtler Mars Lumograph series is known to give a particularly rich black with the softest grades. That may not be relevant to you if you just want them for writing, because I find it practically impossible to write with a wood-cased softer than 4B.

Some fanatics claim that the discontinued Sanford Blackwing 602 was the greatest pencil ever. The lead hardness was about 4B and was unusual for including wax with the graphite and clay. The point wore down quickly, but the lead was particularly resistant to crumbling and it was very slippery on the paper. The line on paper was not as dark as you would expect from a 4B. I would say that the best current pencils give a better line but aren't as slippery. There have been a couple attempts at reproducing the Blackwing, but I've heard mixed reports of how successful they were.

My philosophy of buying pencils is that since there is so little absolute difference in cost between the best and the mediocre, there is no sense in trying to economize there.