I was looking for a way to light up large areas but I'm too used to using wrath lamps or the Thaumcraft lamps, so I added Greg's Lighting to the pack. It's nice but it has some issues. Greg's Lighting adds spotlights that create a line of invisible light emitters along a line about 50 blocks from the lamp. It doesn't interfere with tree growth but if a tree grows in the path, or if you accidentally build into the path of the spotlight it removes all of the invisible lights further along the light path. So by placing one wrong block or a tree growing in the wrong spot you could suddenly have a 50X15 block area go dark. There's a version of the light that uses no power, just 8 blocks of glowstone per spotlight, there's a version that uses water coal and bonemeal, and there's a version that uses IC2 power.
What would be really nice is a stand alone wrath lamp or a tech version of Thaumcraft's lamp. Some way to lessen the tons and tons of torches or glowstone corners spread all over the ground.