Best bang for the Buck would be the Nocturnals. They have consistently proven themselves in test after test to be exceptionally bright, durable and most importantly.... affordable.
One of the highest quality is indeed the Firenock but they are more fragile PLUS if you shoot a bow around 300 fps or faster then you'll need an installation tool to instal and glue a special end cap into the shaft to prevent the internal parts of the nock from blowing forward into the arrow. It's a lot to go through for a nock that costs over $25 EACH!