@Hypermac954 this is a good list. My only addition to what @KaDeTime says is a 1a or 2a:I recommend few things to help,
1. Make a plan what you want to do with the Jeep (rock, overland, weekend warier)
2. Decide final look of the Jeep ( tire size, bumpers, extra items, this will decide the lift and spring tension) get inspired by looking over build post on the web.
3. Get items when you got extra cash and start building
5. Small of the cheap mods are some of the most fun to do
6. And most importantly this is your Jeep make it the way you want it.
Get out there - Go do what you plan to do with the Jeep before you buy anything. The Rubicon is incredibly capable straight out of the gate and you'll find you can do almost anything a first time Jeep owner would want to do. Taking a few trips to places that seem like they fit with your chosen Jeep lifestyle will give you valuable insight into what you actually NEED to buy. 'Getting out there' also has the side benefit of letting you show off the JL and meeting a bunch of likeminded Jeep people who have lots of opinions on aftermarket suppliers and parts.
And if you don't know what you want to do yet, all the better. Just go try everything. Like all the others have said, you'll love it.