IMO, making a melee character is one of the most frustrating aspects of Pathfinder. Traditionally, the fighter or "weaponmaster" is one of my favorite classes in fantasy RPGs. Though, at this point, the fighter has fallen so far behind the other Full BAB classes that it's laughable.
This forum seems to have a love affair with rangers, but... meh. I've attempted to make one for various games on several occasions, but never came up with a build I was happy with. They have a lot going on for them, but that's also their weakness. They're just spread too thing amongst all their various features.
Barbarians are very solid mechanically, and most likely the standard for melees in Pathfinder. Unfortunately, I HATE, HATE, HATE, HATE, HATE the flavor of barbarians. Their rage powers have gotten so out of hand that there is no way I can justify it in an RP sense. They're far more supernatural than martial at this point.
Paladins... not going to lock myself into a LG character, pass.
All in all, I would have to say my favorite melee class is the Summoner. I've found through experience the synergy between a well built summoner and eidolon can flat out be scary. In addition, the summoner winds up being a solid buffer for his eidolon and the party as a whole. Not to mention the battlefield control one brings to the table as well.