Wow. I can't believe it's really over. This show is one of the best - if not the best - examples of television I have ever seen. And while the finale actually wasn't the strongest episode of the season, (that honor remains firmly with Ozymandias) it was still an enormously satisfying conclusion. I really feel like Breaking Bad was a show that respected its viewers. It trusted us to be intelligent. It didn't mess around with our expectations, and it gave us a product of extremely high quality.
So. In this final episode we see Walt go to Gretchen and Elliot Schwartz in their fancy home, ambushing them while they are enjoying an evening alone. He brings in his money and tells them to give it to Walter Jr. when he turns eighteen. In order to solidify this command, Walt threatens them with snipers waiting outside. We later see that the snipers are nothing more than Badger and Skinny Pete with laser pointers. From them, Walt learns that the blue meth is still circulating in the area, and he determines that Jesse is still alive and cooking for Jack.
This scene was really chilling. Walt was so calm about breaking into the Schwartz's home. He didn't sneak around or try and be quiet. He just calmly entered their house and waited to be noticed. It almost seemed like he was having fun as he threatened them with imminent death. I also have to respect Walt's plan, here. He may have found the only way to successfully get that money to his family.