I changed out the halogen interior lights to LED. As Bubbles mentioned, the best deals are on Ebay.
Note that LEDs are polarity dependent. On some types of modules, simply reversing the pins will fix the problem if they don't illuminate when first plugged in. Other times, you may need to reverse the wiring on the light fixture, as some LED modules have all the LED chips mounted on one side of the circuit board which must face in the direction you want. There are also LED modules that have a bridge rectifier circuit installed on the back side of the circuit board that will automatically correct the polarity. These tend to cost about a $1 or so more than the cheapest LEDs at Ebay.
The Chinese LEDs on Ebay don't usually have any brand names, they are just generic. You can buy the same $3 LED in a name brand package at Camping World for $19.95 though...
As for brightness, check to see what model bulbs you presently have installed. Then do a search for the bulb number to find its brightness in lumens. You can then shop LED modules for lumens. You can go brighter or dimmer as you wish, but at least you'll have an idea of where to start. Note that some sellers may exaggerate the brightness.
Another consideration is color temperature. This is measured in degrees Kelvin. It has nothing to do with how hot the LED gets, but rather the color of the light emitted. A warm white LED will be around 3500 degrees, which is a yellowish color similar to a filament light bulb. A bright white LED will be around 6000 degrees, which is more bluish like a fluorescent light. The choice here is yours.
As for power consumption and heat, LEDs typically use about 1/8 the power of a comparable light bulb. Most of that energy savings is from avoiding the wasted heat of a light bulb.
The LEDs on Ebay are cheap enough, so try a few different ones to see what you like.
2010 Georgetown 373
2013 Jeep Wrangler