well to start... halos are just for looks, LED headlight technology isnt far enough long for them to be safe(limited distance).
HID, high intensity discharge lighting is the best you can basically buy right now, however many people go about the upgrade wrong. First off, the PROPER way to install HIDs is only with the use of a projector lens which control the light output and provides an upper cutoff line to the bright light being put out. Yes you can get kits for a direct plug-in into your stock housing but then the light wont focus and its almost worse than driving around with your highbeams on becasue you will be blinding other drivers and in the rain its even more dangerous to oncoming traffic due to the glare.
If you want to keep you sock housings, I would recommend a quality bulb like the sylvania Silverstars and then also polish you headlight assemblies to remove and oxidation from the plastic lens. There are restoration kits you can buy to do that very easily, or use very very fine wet/dry sand paper and a little labor.
If you want HIDs, youd need to upgrade to a whole new housing OR custom fit projector lenses into a stock housing. Obviously the first option is the easiest. From what ive seen, all aftermarket camaro headlights that have projectors also have Halo rings, which just light up dimly to provide a custom high-end look. Halos dont really serve any real purpose. Once you have a projector lens make sure it provides a proper light cutoff and not that the lens is just a cheap piece of glass that truly does nothing. Once thats all good, you can then install one of the plug and play ebay HID kits. They go for about $50 shipped and ive bought them before and had no issues.
I have HIDs in my '01 SS in the stock housings so i know how bright annoying they really are. However i barely drive the car(maybe once every 3 months) and even less at night. Once i get the chance i will be installing the Silverstar 9006 bulbs though.
In my V, i have stock HID headlights and aftermarket HIDs in my foglights. The fogs once again are Very bright and im working on getting projector lenses to mount in them for a custom look and proper setup for those HIDs. That should be done next month.
In my ZR2 Blazer, i will be buying aftermarket headlights with a projector lens so i can install my other set of aftermarket HIDs. Those light i want also have Halo rings which i dont like but i can live with it i think.
so in closing ill say HIDs are best but not in stock housings...
BlackbirdWS6 makes awesome custom HID setups for 4th gens birds, (BLS) so he should be able to answer anymore question about HID setups and i think he'll agree with mainly everything i said.
heres a link to one of his threads...
http://www.njfboa.org/forums/showthread.php?t=49750