Get "The Jeep Owner's Bible" the Haynes Repair Manual for your rig, and the "Jeep 4x4 Performace Handbook". They will be about the best starting point for you to learn some honest to god truths about your rig and the mods out there without getting things too clouded by peoples' (sometimes jaded) opinions. Once you have the facts, opinions make a great fine tuning though. These books will help you make some decisions down the road on which way to go with various upgrades, and the Haynes book will be invaluable once you (inevitably) have to start tearing things apart.
If this is your first Jeep, then congradulations and condolances. It's an addiction.
'98 TJ, 60s, 40s, Comp Cut, Flat Fendered