I really like tempest. The original arcade version is way better than the PS1 remake. And Robotron 2084, though not vector, is a must when I want to have a seizure.

Both embody something that was largely lost in later eras. Today, a lot of games are made so anyone can finish them and feel accomplished. Back then, there was no winning. You were going to die. It was just a question about how high your score would be.