I have my Elvira and the Party Monsters fully LED'd but tastefully so, the GI is mostly a mix of cool and warm whites, with very few colored bulbs, the inserts are all matched properly etc. It doesn't look like a modern monster I guess is my point, tried to keep the LEDs feeling right with the period of the game.
The only thing that's bugged me on it is the blue bottle insert has a blue LED, the insert itself is pretty light in color and white blows it out. The blue is just too intense though, it's over saturated and sticks out as kind of fake with the whole feeling right with the period thing.
I was lucky enough to have Art from http://www.cometpinball.com send me a sample of his new ice blue bulbs, which are really what they sound like, a light blue, like a way colder cool white. I specifically wanted to test it under that blue insert. Happy to say it's way better, feels much more in line with how the game should look. As with all LEDs it's tough to photograph them right, but here's a before and after shot.