Don't go HID in the stock housings, they're not meant for them and could possibly end up in a fine if the police see it.
Best to stick with add-on flood & spot lights but you also need to know your local laws. They can limit you to a certain number of lights and certain height range from the ground. Unless you like covering your offroad lights, it's best to stay within the legal requirements.
That said, LED's are expensive. Light bars can be nice but it's tough to find an affordable and reputable manufacturer. IMO, you're best to stick with PAR style lights since you can swap in/out spot/flood and different wattages in the same housing. Course, there's also halogen with replaceable bulbs or foglights or HID style housings. Many ways to go.
What are your goals, what do you want out of the lights?